[LONG POST - 4 months of trying different planners)

I always wanted to use one but I never thought of analog (paper) planners and tried a lot of digital ones - link to a post.

About 4 months ago I saw my friend at school using a pocket diary - similar to this image, he was writing down his tasks on it (he didn't use it again). That day I bought a good pocket diary of around 200 pages, till date I've not used more than 10 pages and its still lying around.

I realised that I was not going to use it because it was very thick and I couldn't carry it in my pocket. I bought this pocket diary. This was thin and simple, perfect for me. I've used it the longest before switching.

Initially I used to dump all the tasks and cross it after completion, later I introduced a date system and it was one date for one page. I wrote down tasks for the day and crossed after completion if something was incomplete I migrated it to next day. This worked well but I needed a place to dump tasks that I had to do in future so I made a future section from backside and added tasks to it. This was the final tweak and I used it for like a month. I used it for daily tasks, future tasks, some notes and contacts (I used to make contact.txt before this).

Later IIRC I wanted to change because it was already half full and a mess because I was trying to do a lot with it. Next I mindlessly bought a notebook - something like this but with 5 sections, I didn't know what to do with it. I also don't remember why I bought it so I used it to write down stuff that I learned online and wanted to remember. It replaced my reddit save and I wrote what I wanted to remember, it is still with me and has been changed a lot (usecase).

I made a calendar on a single page of that notebook and tracked down basic stuff on it, I started using small square sticky notes to write down tasks and that's how I left my pocket diary. Not long after I lost interest in that notebook thing and updating calendar daily was not interesting. I left that and searched a lot online. Again tried a lot of digital options but I know it will never work for me so I left it and didn't use anything for like a day before I stumbled across Strikethru.

Strikethru is something like Bullet Journal. If you want to look at strikethru then see this video & this for Bullet Journal.

I took that notebook and turned it into a bullet journal, I used it for ~a week before trying strikethru and then again switching to bullet journal after a week. That was testing period and I chosed bulletjournal (bujo) over strikethru. That book was also thick so not long after I made a new bujo notebook (normal 200 pages). Again it felt like a big task that I had to do daily and I lost interest, I again restarted it with a new design. In this month I switched to different notebooks/design a lot and was never satisfied. I also tried Nextcloud tasks for 3 days before again trying out bujo.

Last year in december around a week before christmas I wanted to change it all so I went to a store and bought a new grid notebook (we used it for doing math in 1st grade). I used it for 10 days and everything broke during the last week of december, I was not at home and we went on a vacation. I took it with me but didn't update it because it was boring. It has been 5 days I was busy organising everything else again and now I've settled on what I started with (slightly better idea).

During that time I read a lot on nosurf, pornfree, internet addiction, sleep cycles, polyphasic society, tulpas, made new friends, tried a lot of todo managers, used different journaling apps and this is what I've decided to stay with.

I went to the store today to buy the same pocket diary that I've used the longest (1 month one). Its cheap, for 15 INR and works well for me. Over there I saw a box that said monthly planner, I took it and it had 13 small pocket diaries (similar to what I've used the longest but more thin) and with that a small case that would hold a notebook. There was one contacts pocket diary (perfect) and 12 pocket diaries one for each month. It was for this year and costed 170 INR, I didn't had money so I asked the storeman (idk what we call them, here we call them uncle) did he have cheaper option. He showed me the same piece that costed 140 INR but was for 2016, he said he would give it to me for 70 INR because he would have to throw it anyways.

I thought that was a great deal and bought it. So now I have 12 mini diaries for each month and one contacts diary that has my big list of 10 friends contacts. After trying a lot of different options I came back to what I used for the first time. Its simple and stupid & fits in my pocket.

It has one page for one day and I just have to cross 2016 and the day (mon, tue, etc.) thing and update it with 2019 days. In the middle it has a big two page calendar for current month, page before it has previous months small one page date list to write down events and on page after it has next months small one page date list. The last page is for notes and the cover has 2017 calender that I won't use and ignore.

Theres little patch work todo but for that price I think I bought a good set and if I actually use this for full year then I would buy a new one next one (for 2020 & not 2017 :|)

I've spent around 300 INR for all these (~ 4.5 USD)

Tl;dr -> Used a lot of systems and in the end switched to what I used for the first time which is simple and fits in my pocket.

# What do you use for managing your tasks? Do you use it daily?

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I've found a few really, honestly fantastic open source games and I'd like to share them and discover some new ones too.

Firstly, NullpoMino is a fantastic cross-platform Tetris clone. It's highly, highly customizable and is lots of fun to play. It's got a great community over at Hard Drop, and if you like Tetris - you'll like NullpoMino. However, there are a few issues with it; one in particular being the relatively low skill ceiling of Marathon. The skill ceiling is very low (compared to other titles such as the NES edition), but this is solely exclusive to Marathon as far as I know. It turns into a test of patience rather than skill. Another issue is with installation; as the game was made for 32 bit systems it is rather slow, and it's finicky to run on Linux. However, it is a fantastic Tetris title (and open source!)

Another good open-source game is Osu! I've never played it competitively, but it's a fair bit of fun to play with friends and is a great game. It's cross-platform, although I've only ever played it on Windows, and it has a nice community. Fantastic game that I don't see mentioned too much.

The last game for this post is SuperTuxKart. It serves as a great kart-racing game, that's fun and has a low barrier to entry. Graphically, it's not drop-dead gorgeous, but it's not bad at all either. It's decent solo, and a lot of fun with friends. Would highly recommend. Cross-platform and available as a snap.

On the second week of the new format, we're going to try out themes based on periods of time, this time being the year of 1992. Themes, both years like this one or whatever else you think would work well for the listening club, can be suggested in this thread or if you join the unofficial Tildes Discord server in the #listening-club channel.

Essential Album: Aphex Twin - Selected Ambient Works 85-92 - Listen!

While a lot of excellent and long-lasting work was released in 1992, Selected Ambient Works 85-92 stands out as one of the most influential and has stood the test of time as well as any of them. As much as everyone hates the label of "Intelligent Dance Music" (IDM), there's no doubt that SAW is one of the cornerstone records of that genre that has an impact in the world of music at large that can't be ignored.

Selected Ambient Works 85–92 is the debut studio album by the English electronic musician Richard D. James under the pseudonym of Aphex Twin, released as a very limited import in late November 1992 by Apollo Records, an imprint of the more prominent label R&S Records, and later widely in February 1993. The 1992 LP was James' third release overall, and collected tracks dating back as early as 1985. An analogue remaster was released in 2006, and a digital remaster in 2008.

Selected Ambient Works 85–92 received widespread acclaim and has been characterised as a landmark of electronica, ambient music, and IDM. It was followed by Selected Ambient Works Volume II (1994). On the week ending 27 September 2014, the album entered at #30 in the UK Dance Albums Chart after the release of his 2014 album Syro.

Widely regarded by critics as one of the pioneering works in early IDM and modern electronic music, retrospective reviews mention its influence on electronic artists. Warp Records refers to it as "the birthplace and the benchmark of modern electronic music" and has stated that "every home should have a copy." In 2003, the album was placed #92 in "NME's 100 Best Albums" poll. Nine years later, it was named the greatest album of the 1990s by FACT Magazine. The album was also featured in the book 1001 Albums You Must Hear Before You Die.

Minor Album: Divine Styler - Spiral Walls Containing Autumns of Light - Listen!

This is a strange one, possibly the strangest hip hop album released as of 1992. It's so disjointed and all over the place that instead of describing it myself, I'll steal the descriptors from RateYourMusic: "Islamic, psychedelic, anxious, cryptic, conscious, abstract, introspective, surreal, eclectic, male vocals, avant-garde, noisy, spiritual."

Spiral Walls Containing Autumns of Light is the second album by hip hop artist Divine Styler, released in 1992 on Giant Records. This album marked a significant change in Divine Styler's musical direction, incorporating a much broader range of styles and influences than 1989's Word Power. Despite the album's unusual style, it was actually released by a major label but, perhaps inevitably, failed to sell as well as record executives expected. Although the album was largely regarded as a commercial failure, it has since developed a large cult following. Styler was signed to Giant because of Ice-T’s relationship with Warner Bros. Records.

The album is notoriously experimental—Allmusic referred to the album as being like '"The Residents meets Funkadelic"—and takes influence from a wide variety of music genres such as hip hop, rock, electronic, funk and even elements of spoken word and noise.

The majority of the album was produced and arranged by Divine Styler himself, which included him performing and processing all of the vocals, playing the guitar, drums (and drum programming), and keyboards, among other instruments. Due to the artist's dominance over the album's direction, it is generally regarded as a very introspective and personal album.

Here's the place to discuss your thoughts on the records, your history with them, the artists, or music in 1992 in general and basically talk about whatever you want to that goes along with Selected Ambient Works 85-92 and Spiral Walls Containing Autumns of Light! Remember that this is intended to be a slow moving thing, feel free to take your time and comment at any point in the week!

Again, if you'd like to stream or buy the albums, they can be found on most platforms here (Selected Ambient Works 85-92) and here (Spiral Walls Containing Autumns of Light).

Tildes is currently invite-only. (Thank you redditor u/⎷⎷⎷⎷⎷⎷). Of course, it's in alpha testing, so that makes sense. When do you think tildes will be made public? How will they do it? I don't think it ever really needs to be made public. The reasons are that:
1 - Bans are actual bans. Getting beyond a ban is ridiculously hard compared to on Reddit, where someone just makes a second account. On Tildes, if you're banned, you're banned. That's it. It weeds out a lot of trolls.
2 - Throwaways can't be made. Making a throwaway account on Tildes costs one of your invites, so it's much more annoying to do so.
Hopefully you enjoyed my little rant.

In mid-2012 I decided to become a vegetarian, both for health and ethical reasons. Before then I had mostly been on autopilot when it came to food - I just ate what what was the norm in my family. My choice forced me to get out of my comfort zone, to try out new foods I had never considered before. For this reason, the change has been incredibly positive to me; I'm much more conscious of what I eat now. And by setting a precedent it later helped me make more changes, like cutting down sugar. I'm currently testing to see if the bloating and stomach aches I suffer daily are because I am lactose intolerant; if it is indeed the case, that will require another drastic change, although this particular one will be by necessity rather than choice.

What is the biggest change you've ever made to your diet? Was it by choice, or did you feel obligated to do so, for example because of health issues? What did you get out of it? How much thought do you put in your daily diet, in general?

Preface

Different projects have different use cases that can ultimately result in common solutions not suiting your particular needs. Today I'm going to diverging a bit from my more abstract, generalized topics on code quality and instead focus on a specific project structure example that I encountered.

Background

For a while now, I've found myself being continually frustrated with the state of my project configuration management. I had a single configuration file that would contain all of the configuration options for the various tools I've been using--database, API credentials, etc.--and I kept running into the problem of wanting to test these tools locally while not inadvertently committing and pushing sensitive credentials upstream. For me, part of my security process is ensuring that sensitive access credentials never make it into the repository and to limit access to these credentials to only people who need to be able to access them.

Monolithic Files Cause Monolithic Pain

The first thing I realized was that having a single monolithic configuration file was just terrible practice. There are going to be common configuration options that I want to have in there with default values, such as local database configuration pointing to a database instance running on the same VM as the application. These should always be in the repo, otherwise any dev who spins up an instance of the VM will need to manually tread documentation and copy-paste the missing options into the configuration. This would be incredibly time-consuming, inefficient, and stupid.

I also use different tools which have different configuration options associated with them. Having to dig through a single file containing configuration options for all of these tools to find the ones I need to modify is cumbersome at best. On top of that, having those common configuration options living in the same place that sensitive access credentials do is just asking for a rogue git commit -A to violate the aforementioned security protocol.

Same Problem, Different Structure

My first approach to resolving this problem was breaking the configuration out into separate files, one for each distinct tool. In each file, a "skeleton" config was generated, i.e. each option was given a default empty value. The main config would then only contain config options that are common and shared across the application. To avoid having the sensitive credentials leaked, I then created rules in the .gitignore to exclude these files.

This is where I ran into problem #2. I learned that this just doesn't work. You can either have a file in your repo and have all changes to that file tracked, have the file in your repo and make a local-only change to prevent changes from being tracked, or leave the file out of the repo completely. In my use case, I wanted to be able to leave the file in the repo, treat it as ignored by everyone, and only commit changes to that file when there was a new configuration option I wanted added to it. Git doesn't support this use case whatsoever.

This problem turned out to be really common, but the solution suggested is to have two separate versions of your configuration--one for dev, and one for production--and to have a flag to switch between the two. Given the breaking up of my configuration, I would then need twice as many files to do this, and given my security practices, this would violate the no-upstream rule for sensitive credentials. Worse still, if I had several different kinds of environments with different configuration--local dev, staging, beta, production--then for m such environments and n configuration files, I would need to maintain n*m separate files for configuration alone. Finally, I would need to remember to include a prefix or postfix to each file name any time I needed to retrieve values from a new config file, which is itself an error-prone requirement. Overall, there would be a substantial increase in technical debt. In other words, this approach would not only not help, it would make matters worse!

Borrowing From Linux

After a lot of thought, an idea occurred to me: within Linux systems, there's an /etc/skel/ directory that contains common files that are copied into a new user's home directory when that user is created, e.g. .bashrc and .profile. You can make changes to these files and have them propagate to new users, or you can modify your own personal copy and leave all other new users unaffected. This sounds exactly like the kind of behavior I want to emulate!

Following their example, I took my $APPHOME/config/ directory and placed a skel/ subdirectory inside, which then contained all of the config files with the empty default values within. My .gitignore then looked something like this:

$APPHOME/config/*
!$APPHOME/config/main.php
!$APPHOME/config/skel/
!$APPHOME/config/skel/*
# This last one might not be necessary, but I don't care enough to test it without.

Finally, on deploying my local environment, I simply include a snippet in my script that enters the new skel/ directory and copies any files inside into config/, as long as it doesn't already exist:

cd $APPHOME/config/skel/
for filename in *; do
    if [ ! -f "$APPHOME/config/$filename" ]; then
        cp "$filename" "$APPHOME/config/$filename"
    fi
done

(Note: production environments have a slightly different deployment procedure, as local copies of these config files are saved within a shared directory for all releases to point to via symlink.)

All of these changes ensure that only config/main.php and the files contained within config/skel/ are whitelisted, while all others are ignored, i.e. our local copies that get stored within config/ won't be inadvertently committed and pushed upstream!

Final Thoughts

Common solutions to problems are typically common for a good reason. They're tested, proven, and predictable. But sometimes you find yourself running into cases where the common, well-accepted solution to the problem doesn't work for you. Standards exist to solve a certain class of problems, and sometimes your problem is just different enough for it to matter and for those standards to not apply. Standards are created to address most cases, but edge cases will always exist. In other words, standards are guidelines, not concrete rules.

Sometimes you need to stop thinking about the problem in terms of the standard approach to solving it, and instead break it down into its most abstract, basic form and look for parallels in other solved problems for inspiration. Odds are the problem you're trying to solve isn't as novel as you think it is, and that someone has probably already solved a similar problem before. Parallels, in my experience, are usually a pretty good indicator that you're on the right track.

More importantly, there's a delicate line to tread between needing to use a different approach to solving an edge case problem you have, and needing to restructure your project to eliminate the edge case and allow the standard solution to work. Being able to decide which is more appropriate can have long-lasting repercussions on your ability to manage technical debt.

One thing (amongst many) that always bothered me in my 6+ years of using Reddit was their lax rules about posting clickbait articles and straight up misinformation. In my opinion this was something that contributed to the rise of radical communities and echochambers in the website.

In this post I'll talk about Clickbait, Unreliable studies, and Misinformation. I'll give examples for each one and suggest a way to deal with it.

Clickbait-

Let's start with the most benign one. These days most big websites use clickbait and hyperbole to gain more traffic. It's something that they have to do in order to survive in today's media climate and I sort of understand. But I think that as a community in Tildes we should raise our standards and avoid posting any article that uses clickbait, instead directly link to the source that the article cites.

An example would be: An article titled "Life on Mars found: Scientists claim that they have found traces of life on the red planet".

But when you read the original source it only states that "Mars rover Curiosity has identified a variety of organic molecules" and that "These results do not give us any evidence of life,".
(This may be a bad/exaggrated example but I think it gets my point across.)

On Reddit the mods give these kinds of posts a "Misleading" tag. But the damage is already done, most of the users won't read the entire article or even the source, and instead will make comments based on the headline.
I personally think that these kinds of posts should be deleted even if they get a discussion going in the comments.

Unreliable studies-

This is a bit more serious than clickbait. It's something that I see the most in subjects of psychology, social science and futurism.
These are basically articles about studies that conclude a very interesting result, but when you dig a bit you find that the methodologies used to conduct the study were flawed and that the results are inconclusive.

An (real) example would be: "A new study finds that cutting your time on social media to 30 minutes a day reduces your risk of depression and loneliness"
Link: https://www.businessinsider.com/facebook-instagram-snapchat-social-media-well-being-2018-11

At first glance this looks legit, I even agree with the results. But lets see how this study was conducted:

In the study, 143 undergraduate students were tested over the course of two semesters.

After three weeks, the students were asked questions to assess their mental health across seven different areas

Basically, their test group was 143 students, The test was only conducted for 6 months, and the results were self-reported.

Clearly, this is junk. This study doesn't show anything reliable. Yet still, it received a lot of upvotes on Reddit and there was a lot of discussion going. I only spotted 2-3 comments (at the bottom) mentioning that the study is unreliable.

Again, I think that posts with studies like this should be deleted regardless if there is a discussion going in the comments or not.

Misinformation-

This is in my opinion the biggest offender and the most dangerous one. It's something that I see in political subreddits (even the big ones like /r/politics and /r/worldnews). It's when an article straight up spreads misinformation both in the headline and in the content in order to incite outrage or paint a narrative.

Note: I will give an example that bashes a "left-leaning" article that is against Trump. I'm only doing this because I only read left-leaning to neutral articles and don't go near anything that is right-leaning. Because of this I don't have any examples of a right-leaning article spreading misinformation (I'm sure that there are a lot).

An example would be this article: "ADMINISTRATION ADMITS BORDER DEPLOYMENT WAS A $200 MILLION ELECTION STUNT"
Link: https://www.vanityfair.com/news/2018/11/trump-troops-border-caravan-stunt

There are two lies here:

1. Trump administration did not admit to anything. (The article's use of the word 'Admit' is supposedly justified with 'They indirectly admitted to it'. I personally think this is a bad excuse.)
2. Most importantly, the 200 million figure is pure speculation. If you go to the older article that this article cites, the 200m figure comes from a speculation that the operation could cost up to 200m if the number of troops sent to the border is 15,000 and they stay there for more than 2 months.
   In reality the number of troops sent was 8,500 and they stayed for only a few days/weeks.

A few days after this article was published it turned out that the operation costed 70 million. Still a big sum, still ridiculous. But it's almost a third of what the article claimed.

The misinformation in this example is fairly benign. But I've seen countless other articles with even more outrageous claims that force a certain narrative. This is done by both sides of the political spectrum.

Not only do I think that we should delete these kinds of posts in Tildes, in my opinion we should black list websites that are frequent offenders of spreading misinformation.
Examples off the top of my head would be: Vanity Fair, Salon.com, of course far right websites like Fox News, Info Wars and Breitbart.
A good rule in my opinion would be: If three posts from a certain website get deleted for spreading misinformation, that website should be blacklisted from Tildes.

In conclusion:
I think we should set some rules against these problems while our community is still in the early stages. Right now I don't see any of these 3 problems on Tildes. But if we don't enforce rules against them, they will start to pop up the more users we gain.

I'll be happy to know your opinions and suggestions on the matter!

Preface

Occasionally I feel the need to touch on the subject of code quality, particularly because of the importance of its impact on technical debt, especially as I continue to encounter the effects of technical debt in my own work and do my best to manage it. It's a subject that is unfortunately not emphasized nearly enough in academia.

Background

As a refresher, technical debt is the long-term cost of the design decisions in your code. These costs can manifest in different ways, such as greater difficulty in understanding what your code is doing or making non-breaking changes to it. More generally, these costs manifest as additional time and resources being spent to make some kind of change.

Sometimes these costs aren't things you think to consider. One such consideration is how difficult it might be to upgrade a specific technology in your stack. For example, what if you've built a back-end system that integrates with AWS and you suddenly need to upgrade your SDK? In a small project this might be easy, but what if you've built a system that you've been maintaining for years and it relies heavily on AWS integrations? If the method names, namespaces, argument orders, or anything else has changed between versions, then suddenly you'll need to update every single reference to an AWS-related tool in your code to reflect those changes. In larger software projects, this could be a daunting and incredibly expensive task, spanning potentially weeks or even months of work and testing.

That is, unless you keep those references to a minimum.

A Toy Example

This is where "wrapping" your external libraries comes into play. The concept of "wrapping" basically means to create some other function or object that takes care of operating the functions or object methods that you really want to target. One example might look like this:

<?php

class ImportedClass {
    public function methodThatMightBecomeModified($arg1, $arg2) {
        // Do something.
    }
}

class ImportedClassWrapper {
    private $class_instance = null;

    private function getInstance() {
        if(is_null($this->class_instance)) {
            $this->class_instance = new ImportedClass();
        }

        return $this->class_instance;
    }

    public function wrappedMethod($arg1, $arg2) {
        return $this->getInstance()->methodThatMightBecomeModified($arg1, $arg2);
    }
}

?>

Updating Tools Doesn't Have to Suck

Imagine that our ImportedClass has some important new features that we need to make use of that are only available in the most recent version, and we're several versions behind. The problem, of course, is that there were a lot of changes that ended up being made between our current version and the new version. For example, ImportedClass is now called NewImportedClass. On top of that, methodThatMightBecomeModified is now called methodThatWasModified, and the argument order ended up getting switched around!

Now imagine that we were directly calling new ImportedClass() in many different places in our code, as well as directly invoking methodThatMightBecomeModified:

<?php

$imported_class_instance = new ImportedClass();
$imported_class_instance->methodThatMightBeModified($val1, $val2);

?>

For every single instance in our code, we need to perform a replacement. There is a linear or--in terms of Big-O notation--a complexity of O(n) to make these replacements. If we assume that we only ever used this one method, and we used it 100 times, then there are 100 instances of new ImportClass() to update and another 100 instances of the method invocation, equaling 200 lines of code to change. Furthermore, we need to remember each of the replacements that need to be made and carefully avoid making any errors in the process. This is clearly non-ideal.

Now imagine that we chose instead to use the wrapper object:

<?php

$imported_class_wrapper = new ImportedClassWrapper();
$imported_class_wrapper->wrappedMethod($val1, $val2);

?>

Our updates are now limited only to the wrapper class:

<?php

class ImportedClassWrapper {
    private $class_instance = null;

    private function getInstance() {
        if(is_null($this->class_instance)) {
            $this->class_instance = new NewImportedClass();
        }

        return $this->class_instance;
    }

    public function wrappedMethod($arg1, $arg2) {
        return $this->getInstance()->methodThatWasModified($arg2, $arg1);
    }
}

?>

Rather than making changes to 200 lines of code, we've now made changes to only 2. What was once an O(n) complexity change has now turned into an O(1) complexity change to make this upgrade. Not bad for a few extra lines of code!

A Practical Example

Toy problems are all well and good, but how does this translate to reality?

Well, I ran into such a problem myself once. Running MongoDB with PHP requires the use of an external driver, and this driver provides an object representing a MongoDB ObjectId. I needed to perform a migration from one hosting provider over to a new cloud hosting provider, with the application and database services, which were originally hosted on the same physical machine, hosted on separate servers. For security reasons, this required an upgrade to a newer version of MongoDB, which in turn required an upgrade to a newer version of the driver.

This upgrade resulted in many of the calls to new MongoId() failing, because the old version of the driver would accept empty strings and other invalid ID strings and default to generating a new ObjectId, whereas the new version of the driver treated invalid ID strings as failing errors. And there were many, many cases where invalid strings were being passed into the constructor.

Even after spending hours replacing the (literally) several dozen instances of the constructor calls, there were still some places in the code where invalid strings managed to get passed in. This made for a very costly upgrade.

The bugs were easy to fix after the initial replacements, though. After wrapping new MongoId() inside of a wrapper function, a few additional conditional statements inside of the new function resolved the bugs without having to dig around the rest of the code base.

Final Thoughts

This is one of those lessons that you don't fully appreciate until you've experienced the technical debt of an unwrapped external library first-hand. Code quality is an active effort, but a worthwhile one. It requires you to be willing to throw away potentially hours or even days of work when you realize that something needs to change, because you're thinking about how to keep yourself from banging your head against a wall later down the line instead of thinking only about how to finish up your current task.

"Work smarter, not harder" means putting in some hard work upfront to keep your technical debt under control.

That's all for now, and remember: don't be fools, wrap your external tools.

C:

int main(void)
{
	puts("test");
	return 0;
}

Go:

package main

import "os"

func main() {
	_, err := os.Stdout.WriteString("test")
	if err != nil {
		_, _ = os.Stderr.WriteString("fail")
	}
}

Ruby:

10.times { |n| puts "test_#{ n }" }

XML:

<html>
  <body>
    <h1>test</h1>
  </body>
</html>

EDIT: With the help of @ducks the post now has illustrations to clear up the experimental set-up.

Introduction

I want to give an introduction on several physics topics at a level understandable to laypeople (high school level physics background). Making physics accessible to laypeople is a much discussed topic at universities. It can be very hard to translate the professional terms into a language understandable by people outside the field. So I will take this opportunity to challenge myself to (hopefully) create an understandable introduction to interesting topics in modern physics. To this end, I will take liberties in explaining things, and not always go for full scientific accuracy, while hopefully still getting the core concepts across. If a more in-depth explanation is wanted, please ask in the comments and I will do my best to answer.

Previous topics

Spintronics
Quantum Oscillations
Quantisation and spin, part 1

Today's topic

Today's topic will be a continuation of the topics discussed in my last post. So if you haven't, please read part 1 first (see link above). We will be sending particles through two Stern-Gerlach apparatuses and then we'll put the particles through three of them. We will discuss our observations and draw some very interesting conclusions from it on the quantum nature of our universe. Not bad for a single experiment that can be performed easily!

Rotating the Stern-Gerlach apparatus

We will start simple and rotate the set-up of the last post 90 degrees so that the magnets face left and right instead of up and down. Now let's think for a moment what we expect would happen if we sent silver atoms through this setup. Logically, there should not be in any difference in outcome if we rotate our experiment 90 degrees (neglecting gravity, whose strength is very low compared to the strength of the magnets). This is a core concept of physics, there are no "privileged" frames of reference in which the results would be more correct. So it is reasonable to assume that the atoms would split left and right in the same way they split up and down last time. This is indeed what happens when we perform the experiment. Great!

Two Stern-Gerlach apparatuses

Let's continue our discussion by chaining two Stern-Gerlach apparatuses together. The first apparatus will be oriented up-down, the second one left-right. We will be sending silver atoms with unknown spin through the first apparatus. As we learned in the previous post, this will cause them to separate into spin-up and spin-down states. Now we take only the spin-up silver atoms and send them into the second apparatus, which is rotated 90 degrees compared to the first one. Let's think for a moment what we expect would happen. It would be reasonable to assume that spin-left and spin-right would both appear 50% of the time, even if the silver atoms all have spin-up too. We don't really have a reason to assume a particle cannot both have spin up and spin right, or spin up and spin left. And indeed, once again we find a 50% split between spin-left and spin-right at the end of our second apparatus. Illustration here.

Three Stern-Gerlach apparatuses and a massive violation of common sense

So it would seem silver atoms have spin up or down as a property, and spin left or spin right as another property. Makes sense to me. To be sure, we take all the silver atoms that went up at the end of the first apparatus and right at the end of the second apparatus and send them through a third apparatus which is oriented up-down (so the same way as the first). Surely, all these atoms are spin-up so they will all come out up top again. We test this and find... a 50-50 split between up and down. Wait, what?

Remember that in the previous post I briefly mentioned that if you take two apparatuses who are both up-down oriented and send only the spin-up atoms through the second one they all come out up top again. So why now suddenly do they decide to split 50-50 again? We have to conclude that being forced to choose spin-left or spin-right causes the atoms to forget if they were spin-up or spin-down.

This result forces us to fundamentally reconsider how we describe the universe. We have to introduce the concepts of superposition and wave function collapse to be able to explain these results.

Superpositions, collapse and the meaning of observing in quantum physics

The way physicists make sense of the kind of behaviour described above is by saying the particles start out in a superposition; before the first experiment they are 50% in the up-state and 50% in the down-state at the same time. We can write this as 50%[spin up]+50%[spin down], and we call this a wave function. Once we send the particles through the first Stern-Gerlach apparatus each one will be forced to choose to exhibit spin-up or spin-down behaviour. At this point they are said to undergo (wave function) collapse; they are now in either the 100%[spin up] or 100%[spin down] state. This is the meaning of observing in quantum mechanics, once we interact with a property of an atom (or any particle, or even a cat) that is in a superposition this superposition is forced to collapse into a single definite state, in this case the property spin is in a superposition and upon observing is forced to collapse to spin up or spin down.

However, once we send our particles through the second apparatus, they are forced to collapse into 100%[spin left] or 100%[spin right]. As we saw above, this somehow also makes them go back into the 50%[spin up]+50%[spin down] state. The particles cannot collapse into both a definite [spin up] or [spin down] state and a definite [spin left] or [spin right] state. Knowing one precludes knowing the other. An illustration can be seen here.

This has far reaching consequences for how knowable our universe it. Even if we can perfectly describe the universe and everything in it, we still cannot know such simple things as whether a silver atom will go left or right in a magnetic field - if we know it would go up or down. It's not just that we aren't good enough at measuring, it's fundamentally unknowable. Our universe is inherently random.

Conclusion

In these two posts we have broken the laws of classical physics and were forced to create a whole new theory to describe how our universe works. We found out our universe is unknowable and inherently random. Even if we could know all the information of the state our universe is in right now, we still would not be able to track perfectly how our universe would evolve, due to the inherent chance that is baked into it.

Next time

Well that was quite mind-blowing. Next time I might discuss fermions vs bosons, two types of particles that classify all (normal) matter in the universe and that have wildly different properties. But first @ducks will take over this series for a few posts and talk about classical physics and engineering.

Feedback

As always, please feel free to ask for clarification and give me feedback on which parts of the post could me made clearer. Feel free to discuss the implications for humanity to exist in a universe that is inherently random and unknowable.

Addendum

Observant readers might argue that in this particular case we could just as well have described spin as a simple property that will align itself to the magnets. However, we find the same type of behaviour happens with angles other than 90 degrees. Say the second apparatus is at an angle phi to the first apparatus, then the chance of the particles deflecting one way is cos^2(phi/2)[up] and sin^2(phi/2)[down]. So even if there's only a 1 degree difference between the two apparatuses, there's still a chance that the spin will come out 89 degrees rotated rather than 1 degree rotated.

I'd really like to have a DNA test done to know my family history beyond 2 generations (adopted relatives)

I've heard numerous times that 23andme will abuse the information they obtain and either target you with ads or sell your DNA to marketing agencies, are there any non invasive DNA tests available online or elsewhere?

Here’s a problem I had to solve at work this week that I enjoyed solving. I think it’s a good programming challenge that will test if you really grok XML.

Your input is some XML such as this:

<DOC>
<TEXT PARTNO="000">
<TAG ID="3">This</TAG> is <TAG ID="0">some *JUNK* data</TAG> .
</TEXT>
<TEXT PARTNO="001">
*FOO* Sometimes <TAG ID="1">tags in <TAG ID="0">the data</TAG> are nested</TAG> .
</TEXT>
<TEXT PARTNO="002">
In addition to <TAG ID="1">nested tags</TAG> , sometimes there is also <TAG ID="2">junk</TAG> we need to ignore .
</TEXT>
<TEXT PARTNO="003">*BAR*-1
<TAG ID="2">Junk</TAG> is marked by uppercase characters between asterisks and can also optionally be followed by a dash and then one or more digits . *JUNK*-123
</TEXT>
<TEXT PARTNO="004">
Note that <TAG ID="4">*this*</TAG> is just emphasized . It's not <TAG ID="2">junk</TAG> !
</TEXT>
</DOC>

The above XML has so-called in-line textual annotations because the XML <TAG> elements are embedded within the document text itself.

Your goal is to convert the in-line XML annotations to so-called stand-off annotations where the text is separated from the annotations and the annotations refer to the text via slicing into the text as a character array with starting and ending character offsets. While in-line annotations are more human-readable, stand-off annotations are equally machine-readable, and stand-off annotations can be modified without changing the document content itself (the text is immutable).

The challenge, then, is to convert to a stand-off JSON format that includes the plain-text of the document and the XML tag annotations grouped by their tag element IDs. In order to preserve the annotation information from the original XML, you must keep track of each <TAG>’s starting and ending character offset within the plain-text of the document. The plain-text is defined as the character data in the XML document ignoring any junk. We’ll define junk as one or more uppercase ASCII characters [A-Z]+ between two *, and optionally a trailing dash - followed by any number of digits [0-9]+.

Here is the desired JSON output for the above example to test your solution:

{
  "data": "\nThis is some data .\n\n\nSometimes tags in the data are nested .\n\n\nIn addition to nested tags , sometimes there is also junk we need to ignore .\n\nJunk is marked by uppercase characters between asterisks and can also optionally be followed by a dash and then one or more digits . \n\nNote that *this* is just emphasized . It's not junk !\n\n",
  "entities": [
    {
      "id": 0,
      "mentions": [
        {
          "start": 9,
          "end": 18,
          "id": 0,
          "text": "some data"
        },
        {
          "start": 41,
          "end": 49,
          "id": 0,
          "text": "the data"
        }
      ]
    },
    {
      "id": 1,
      "mentions": [
        {
          "start": 33,
          "end": 60,
          "id": 1,
          "text": "tags in the data are nested"
        },
        {
          "start": 80,
          "end": 91,
          "id": 1,
          "text": "nested tags"
        }
      ]
    },
    {
      "id": 2,
      "mentions": [
        {
          "start": 118,
          "end": 122,
          "id": 2,
          "text": "junk"
        },
        {
          "start": 144,
          "end": 148,
          "id": 2,
          "text": "Junk"
        },
        {
          "start": 326,
          "end": 330,
          "id": 2,
          "text": "junk"
        }
      ]
    },
    {
      "id": 3,
      "mentions": [
        {
          "start": 1,
          "end": 5,
          "id": 3,
          "text": "This"
        }
      ]
    },
    {
      "id": 4,
      "mentions": [
        {
          "start": 289,
          "end": 295,
          "id": 4,
          "text": "*this*"
        }
      ]
    }
  ]
}

Python 3 solution here.

If you need a hint, see if you can find an event-based XML parser (or if you’re feeling really motivated, write your own).

I was watching my favorite weekly space show on YouTube, TMRO, and I learned about Astro Live Experiences (ALE.) They will soon launch two test satellites which will be able to provide a burst of 30-40 man made shooting stars at a prearranged time and place, for a fee.

Japanese company ALE is the first "space entertainment" company of which I am aware. The only event in the same ballpark was New Zealand based RocketLab's Humanity Star which caused a large amount of controversy. ALE's initial technology will allow a 200km radius of earth to see their multi-color shooting star show. According to the interview on TMRO, in the long term, they are planning to allow image rendering and even artificial aurora.

This type of business seems inevitable as we advance into space. I can see some benefits and some downsides to this technology. What do you all think of this?

^{Maybe this topic belongs in ~misc}