November Meditations

Throughout the month of November I finally found the time to clear my list thoughts and observations about everyday life. This is a project that I have started since summer, and while some answers were not thorough, I can honestly say that the observations made and the habit of constantly thinking has served me tremendously.

This doesn’t mean I’m done thinking about life questions. I believe that there will be a new wave of questions when I start reading rationalist literature. However, the questions will probably come less frequently now, as I shift my focus toward acquiring new skills.

EDIT: To improve readability, I grouped my thoughts loosely into five groups: self-efficacy, execution, communication, metaphysics, and personal notes. This way, the thoughts are arranged in order of averageness to the reader, and there’s room for breaks. Have fun!


  1. One of the best free things you can get is to listen to criticism. The better you are at accepting them, the more your abilities will skyrocket. It is easy for people to criticize, so they will gladly do it. However, the end product is something that combines a unique perspective and (hopefully) good taste in a small amount of time. Collect all the criticisms, especially from people you respect! They are cheap and immensely useful.
  2. A good metaphor for criticism is as getting what other’s people prior on “what’s good” is, then clustering to get something that bests all individual parts.
  3. Along the same line as above, another free thing is to critically examine your own work. Once you get over the initial “ugh”, you will learn how to improve, and learn about the act of improving.
  4. Don’t let the previous two rules affect your confidence. If they have, you have taken the criticism personally. Try to never take criticisms personally.
  5. Innate ability is overrated.
  6. People seek a high-or-impossible-level of certainly when answering some specific questions relating to self-confidence or morality. This may prevent them from taking certain risks or feel comfortable as themselves.
  7. Normality often does not have intrinsic value. In the art world, they might actually have negative value. Try at times to see without the lens of normality. This could entail seeing something as if you are looking at it for the first time or imagining something to be a lot more different than what you think it is.
  8. People are scared of thinking for several reasons: 1.) nationalism often try to combat critical thinking 2.) thinking usually implies going into the unfamiliar, which is scary to many people. Under this narrative, it is very easy to persuade people to be afraid of thinking.
  9. Do not care about college rankings. In fact, do not care about the ranking of anything you didn’t help in creating. In fact, do not care about rankings of random people. There’s too much variance.
  10. If you find yourself caring too much about what other things, consider whether you have been exposed currently to any other criteria for judging quality. It is natural to use public opinion as a basis, and it is oftentimes the default criteria on which performances are measured.
  11. Worldly success is not necessarily a more reliable indicator of satisfaction than affinity to reason.
  12. Loving others are work is not mutually exclusive.
  13. Ability to be critical is one of the most important aspect of the arts. It defines the ceiling of one’s accomplishments.
  14. For personal growth, try to understand yourself relative to others. The more you know about where you stand in comparison to others, the easier it is to be confident.
  15. Strength of ambition and clarity of goals usually end up determining how far people will go.
  16. Find internal motivations rather than external motivations.
  17. From an economical perspective, it makes sense for people to stagger their replies (at this with the current means of communication).
  18. Use movies/games at the right time can do a lot to relieve stress or isolation.
  19. System 1 (consult Thinking Fast and Slow) is bad for making decisions about self-worth or proficiency. Avoid using system one for these evaluation.
  20. Your rate of decrease in self-confidence, in case where your find yourself contradicting or distancing the people you respect, should be proportional to duration of distancing and inversely proportional to amount of personal experience. Apply a lot of reasoning and care before lowering self-confidence. This should drop very slowly: barely for a long time, then exponentially with more drop-off in light of higher/repeated durations of distancing.
  21. Don’t try to learn things for the sake of impressing others. It’s not a very consistent motivator.


  1. Errors/delays are more costly the longer they are in place, but this rate of cost increase is very dependent on the original task. In this way tasks can be strategically prioritized.
  2. Some would consider reading productive, but I think it only is so when the reader is specifically aiming for breadth or depth in a particular topic. Articles and aimless readings lags in productivity when compared to direct thinking.
  3. Freedom is deceptive. Suppose there is a tradeoff between options to do normal things and ability to accomplish more interesting things. In this case, I think one increases freedom by giving up the prior for the latter. Metaphorically, spaces that contain possibilities that interest you can be considered much more dense in freedom than spaces containing uninteresting possibilities, since the prior is what we want to accomplish anyway. It can be liberating to give up a lot of uninteresting options for small additional possibilities in the interesting options.
  4. Vertical set of skills/knowledge in a domain increase quality and speed. Horizontal set of skills/knowledge in a domain increases possible outcomes and novelty. The speed increase in prior mainly comes from superior debugging abilities.
  5. Other than speaking, writing is the most straightforward way to showcase mental abilities and persuade. The process aids thinking as well.
  6. We are hardwired to pay attention to certain things: other people, things about me, free things, danger, bright lights, etc. When thinking, it is best to be on a path that avoids such potential distractions. Using earbuds & sunglasses to block out signals is usually fairly effective.
  7. To a certain extent distractions are useful because they are also where interesting thoughts may emerge. A potentially good way to monitor distractions is to backtrace the source of the thought, determine whether similar distractions might be potentially useful, and to find ways to prevent that distraction from occurring again if not.
  8. For me, attention often disintegrates when the body is under stress. Lack of attention is noticeable and almost always associated with tiredness. This makes exercise a higher priority.
  9. Some systems, such as art or stock markets, are chaotic enough such that building an accurate mental model is tough to impossible. In such cases, try to get a ton of data points and approximate a mental model, but make it flexible enough to add new information.
  10. Should we spend our life doing small good things or build up to a larger good? I have yet to hear a convincing argument that prefers the prior or the latter, since the latter is understood to grow faster than linear.
  11. Invest in epistemic curiosity, even if it might not seem directly relevant to goals. No need to act on the curiosity, but opportunity to satisfy them might often present itself.
  12. Prioritize different tasks based on their expected utility and the dependence of that utility upon time. For example, many tasks are not time sensitive, so they could be drastically delayed.
  13. It is notable that ideologies can sometimes produce incredible results by removing the sense of doubt that was in the way. This might be how people face up to tasks that seem impossible. A potentially useful application of ideologies may to bet on heuristics that you are not certain of but seems immensely powerful if do believed and low risk if not in fact true. For example: never stop creating.
  14. As in the case of taking feedback, ego often stands in the way of progress. Recognizing when ego stands in the way and removing such obstacles is a painful task, but this makes it more worthwhile because it’s something with lifelong benefits and something that others seldom do.
  15. To read books productively (not to be confused with leisurely). Read the book and take notes so that you will only be reading it once. Skim if necessary. Group books on similar topics to similar time periods so that the subject matter is almost the top thing on your mind for that time period. This is crucial for any complicated subjects.
  16. It is easy to criticize a work, but difficult to appreciate one. The previous tells us what not to do, but the latter can tell us what do to, which is augmented by what not to do when you want to do it. This can be really valuable! Every strength and flaw exist for a reason, and to be able to find what makes a strength a strength and why it was lost can be useful. This especially applies to works where the author attempts to address something personal and important, as these tend to tell you the most valuable things about the human condition.
  17. Rules of optimal multiplexing (multi-tasking): multiplexing is useful in two scenarios, a.) when you are in a situation where multiple tasks can be done without competing for cognitive resources, e.g. listening to audiobooks while driving or in longer terms, thinking about the future while working on a desired job. b.) when two tasks performed together gives rise to an interconnectedness than can be expected to improve both, e.g. talking a walk while thinking, learning about neuroscience and artificial intelligence at the same time. Note that both a.) and b.) applies to both short term and long term time scales. Outside of these contexts, context switch is too expensive to pursue tasks in parallel. If multiple things need to be accomplished in short order, parallelize related ones and serialize the others.
  18. The useful parts of history concern change – getting data about change allows you to fully understand why the current state of things are what they are, what could be changed, what needs to happen to instigate that change, what is currently changing, and what is completely unexplored. However, learning about history is also costly in terms of time investment and domain specificity. It’s a heavyhanded tool. I suggest using it on domains where you have a strong desire to excel in.
  19. Acknowledging that your way to think is not the only efficient/correct way to think is likely a good proposition. This should in theory be treated the same as any question – bayesian reasoning should be used to determine the answer. However, but since this question may have wide implications on the evolution of your thoughts, extra care should be taken to avoid ideologies forming.
  20. It’s better to opt-out of having any sides in absence of information. Try to maintain and be consistent and well-calibrated with your confidence levels.
  21. Time not spent on a task is basically time gained.
  22. When a constraint seriously limit your options, consider moving to an area where the presence of the constraint has no effect on the result. This is equal to removing a constraint entirely.
  23. Looking at things from economical perspectives remove a lot of potential anguish. Often it is the case that instead of decrying that the public lacks some moral quality, considering the phenomenon as a problem to be systematically solved is more effective. Even without proposing a solution, the economical view can be liberating in removing the sense of anguish (such as “why did we only care about ISIS when France gets attacked?”).
  24. It’s easy to enter a state of “tunnel vision” when one determines a fixed method to approach a goal and focus on the method rather than the goal. Try to step back and reconsider potential other methods at times.
  25. Like things broadly to keep yourself open and sociable, but keep a level of critical judgement even on new subjects. Liking things broadly is especially useful for world-building.
  26. There are several explanations on why people get their “just desserts”, whether for good or for bad things. It is probably possible to maximize for fortitudinous encounters.
  27. If a problem recurs, try either specify the problem more or root cause analysis.  Lack of the first tool leads to misplaced faith, whereas the second one recounts recurring problems. Need to figure out which one is the case.
  28. Heuristics like those listed here needs to be double-checked if used in high-risk scenarios.
  29. Rationalism is a dangerous banner. Do not assume that your ideas are bullet-proof because you are a rationalist.
  30. When it comes to people, quality trumps quantity.
  31. Most choices in life can be describe in terms of the good and the bad. When considering these choices, replace positive and negative connotations with neutral ones first, and assume that the speaker has no authority.
  32. Beware of adages and spiritual wisdoms. Consider whether the source has biases, of whether a lack of clear reasoning is intentionally or unintentionally obfuscated.
  33. Drive and energy is the raw fuel that converts to execution. Other ways to be better at doing things: let nothing stand in the way, especially personal feelings. Be willing to do what is good for the goal. Study how people works. Try to allocate more resources to planning. Drop small priorities.
  34. It’s ok to drift apart from your goal, as long as you keep your eyes on the goal and know a course back.
  35. Whether learning or doing, use things you passionate about to motivate you.
  36. Approach large tasks methodologically, breaking larger tasks to smaller tasks if performance is struggling. Do not take too long to find out whether you are struggling or not by checking yourself for improvements.
  37. Timebox you training activities per day.
  38. Keep concentration by increasing components of feedback in your work, holding yourself to high standards, and having clear goals.
  39. Compare your works to that of the very best. AB test.
  40. For quality of work, do not expect skills to be acquired within a rigid time frame.


  1. I find blogs to be my preferred method for facilitating conversations for several reasons, and these correspond somewhat to reasons I find 1-on-1 conversations more pleasant. Participation of discussions in blogs are not only voluntary, but actually has a higher barrier to entry than social media. This sets a higher bar for the quality of discussions. On blog sites there are usually very few distractions pulling people away from their thoughts, and the writer is less subject to judgement from outsiders than on social media. Email is theoretically as good, but lack the sense of permanence that blog posts have.
  2. Delays may serve as a communication tool in any medium, not just conversation.
  3. Conversation can be seen as tango. The goal is to make the other person feel great coming out of the conversation. Just as in tango, it is required to a certain extent that the other person is interested in conversation. The leading partner in tango seeks joy through micro-adjusting the dance to create an optimal experience for the follower, and this entails knowing what the other person knows and wants. The leading person in a conversation very much does the same thing.
  4. The quality of any form of communication (e.g. art, writing) depends strongly on its coherence.
  5. Lack of coherence emerges often from multiple sessions of modifications, since each approach comes with slightly different mindset. This can be combatted through refactoring or simply becoming faster at finishing a work. Forming a habit of finishing work fast is useful in multiple ways, but I think this is one of the most useful.
  6. A lot of subtle sources of emotions can probably be attributes to small units of tension that builds up over time – similar to how music and movies build musical and visual tensions, people walk around with everyday sources tensions that can make seemingly small validations feel important to a person. I think this is likely why people attribute so much personal significance to their unpopular view points or idiosyncrasies.
  7. The sea is probably the ultimate metaphor for pretty much everything.
  8. Art is uniquely adept at showing what I call “eternal problems”, problems that we can ask ourselves but often cannot commit an answer to. For example: individualism vs. collectivism. The ones that are fitting for art are often sensitive or painful problems.
  9. Do what dogcopter says.
  10. When people of different status levels interact, a certain sense of imbalance ensues if both parties are strongly aware and affected by the imbalance in status. I feel that this often degrades quality of interaction. Since this mostly ensues if both parties feel affected by it, try to not be intimidated by the other person’s status to keep your interactions of quality.
  11. The best artworks seems to be very personal to the author, but somehow becomes personal to everyone too.
  12. People are incredibly varied in their tastes and mindset. This is always something useful to keep in mind.
  13. Gender carries innate symbolism, just as the sun, the Earth, and the moon does. Given the current political atmosphere, this is something good to keep in mind.
  14. Most likely, most people confronted a question of gender roles as a child or teenager.
  15. Taking the less aggressive stance in a debate is almost always beneficial because a.) you restrain yourself from radicalization. b.) the conversation remains friendly c.) you are more likely to analyze arguments well d.) you remove your ego from the conversation.
  16. Perfect works of art are rare. An important trade-off may need to be made at times between quality and attractiveness (ability to tell the viewer that the work has potential for something great). I think timeless works often have both.
  17. The biggest reason that poems about simple happiness so rare is probably because it is difficult to empathize with happiness.
  18. “Art is suffering” implies that the alternative is… somehow worse.
  19. Miyazaki suspects that artistic work is a glorified hobby, but I don’t think this is the case. Meaningful work seek to be useful to others, and like technology, art is useful in a different hierarchy of need.
  20. Dancing is a unique form of art that can be incredibly powerful in it’s expression of energy, life-affirmation, and love. Respect the power of dance as a medium.
  21. We often regard things that can be permanently lost as good or beautiful.
  22. Word-of-mouth recommendations > good reviews.
  23. Advise without sufficient motivation or explanation can be mistaken as “agenda”. Justify your thesis, whether emotional or rational.
  24. People with stronger sense of self-expression tends to keep a list of favorite things and like to remind people about them.
  25. Don’t be overly novel without justification.

Metaphysics (somewhat)

  1. On seeing overachievers on an epic scale, we tend to like to call them “robot” or “superhuman”, even though the connotations are quite different. This says a lot about the human condition. There are fixed traits that makes us emphasize with another more, such as holding back lower forms of desires, fighting exhaustion and apathy, and dealing with negative emotions. On the other hand, if the “hero” does not ostensibly experience these traits, we tend to antagonize them instead. This antagonization very likely comes from the notion that our struggles are perceived as pointless, and any struggles characterized as “pointless” deeply offends the human psyche. I suspect that there’s a bit of jealousy in the mix too. In the end, what we collective antagonize and envy tells us volumes about the human condition.
  2. People seek validation, empathy, and and freedom from judgement in conversation.
  3. Reasons people need sources of motivation: to feel closer to their goals, to feel powerful (which make problems look less threatening), to feel successful, and to feel surrounded by others who are similar to them (validation).
  4. Try to ask specific questions so that a.) it’s easier to dwell on them without getting distracted b.) reasonings are seamlessly linked and c.) resulting thoughts are more robust.
  5. Fast robust reasoning often comes from chained heuristics. Given good enough quality of constructing heuristics, one can chain more of them together with less likelihood of failure. Heuristics are not suitable for riskier tasks (if potential loss is high).
  6. Strange ideologies are almost always bad in the long run. These ideologies exist (or are unintentionally created) to round out potential doubts on a good heuristic, but unless the heuristics is very good, ideologies will render people unable to change. This is a huge flaw.
  7. Any space within which items can change with time can be thought of abstractly as a field that maps differential equations, along with potential probability associated with future directions so that the space can be seen as non-deterministic. This provides a mental model within which we can reason about things like the nature of decisions and potential.
  8. There is a difference between innocent vs. pure. One has knowledge while the other does not.
  9. The emphasis on obeying social structure in collectivist societies may remove people from rationalist mindsets and make them subscribed to ideologies rather than seeing them as just heuristics.
  10. Saying that “p implies q does not imply q implies p” is strictly correct, but potentially misleading.  In real life, Baye’s rule says multiple correlations can be used to deduce very strong possibilities of causation.
  11. Certain groups of people are strongly moved by what they consider “perfection”.
  12. Another way that we are not equal at birth is that some people may be attracted to things deemed harmful by society. However, I believe that the society’s laws are an approximation of the rule “do not harm others”, and I think in many ambiguous situations the moral principle of no harm should be considered the guiding star. There are no questions though that some are born to bear a burden this way.
  13. Most questions we ask are underspecified. Such answers simply have no catch-all solutions. For example, “political correctness or freedom of speech?” is a question that is insanely dependent on the situation, but people have a tendency of liking to find such catch-all solutions to simply their viewpoint and to solidify a kind of self-identity. The attraction of narrative make people lean toward absolutes. In reality, the question should be sliced to different contexts, which either requires a lot of work or is impossible. Such are the work of court judges.
  14. Questions that you thought you solved but continues to come back are nag you are probably underspecified.
  15. Heuristics can be described as approximate answers to questions that are surprisingly not-underspecified.
  16. Common life scenarios (e.g. working at a grocery store, or going to school) do not present a good average of different possible range of personal values, and so it is very easy for people to adopt strange world views that seem natural in the context of their environment. We have an illusion that what we see represents the world accurately, when that is not actually the case. Things that personal survival depends on (or have the illusion of depending on) has the highest influence on personal values.
  17. Responsibility implies mutual contract that was expected to be fulfilled. Being sacrificed for or sacrificing for someone does not indicate the presence of responsibility – it indicates a potentially a wish for another person to fulfill a post-the-fact contract. This is an undesirable way to approach things.
  18. Society operates on mutually-beneficial contracts.
  19. For whatever reason, people seek for sensations that remove a sense of ego. For example, religious community, meditation, flow-inducing activities, nature, nationalism, love, pursuit of aesthetic beauty… Activities that diminishes the ego are seen as pleasing, if not spiritual. This is prevalent enough to be considered as a possible definition of the spiritual.
  20. Most people’s self-actualization involves some sort of service to the greater community in the end, if only to justify what they like to do. There’s an innate sense that serving others is the highest goal.
  21. People’s affinity for spirituality and community  are some of the biggest driving forces in the world. This is what compels people to write, pursue art, devote themselves to ideologies, make sacrifices, and more. A significant amount of human activities can be seen as fulfilling a need that is either spiritual, communal, or both.
  22. Those who choose not to believe in science or philosophy are behaving as such because they are in a local maximum of life-satisfaction. If the process of switching to science and philosophy will incur a loss of satisfaction in the short term, then it will make sense from their perspective to hold on to their beliefs. It is perhaps possible that the process may incur loss of satisfaction in the long term, in which case we would be hard-pressed to criticize it, since science and philosophy themselves operates on the principle of practicality.
  23. Most proposition about the world can be seen as functions. When looking for functions, we are restricted by our memory to hold easy-to-remember functions, preferably non-compound ones. When this is the case, we can derive knowledge.
  24. Proposition connect at least two concepts from different spaces. “Are people good” considers “people” and “good”. To break down a proposition, consider other candidates for both (or all) of the spaces that the proposition connects, or more clearly define concepts involved.

Personal notes

  1. I should be constantly aware of the ways I talk to others and seek to improve it.
  2. I notice countless things, even unusual observations, without them reaching far enough into my consciousness to be seriously considered. I need to be more mindful of these occurrences.
  3. I can probably shell out about ~30 hours of work per week on any subject of choice.
  4. Subscribing to the mythos of independence can be harmful sometimes, especially considering the description of freedom in the execution section. Keep the option of having a team open.
  5. Some strands of thought can be tell-tale signs that some sort of self-deceiving reasoning is about to take place – e.g. guilt, the desire to avoid things, laziness, snarkiness, thinking of something as “beyond reason”.
  6. What I want in life seems not so different than from 4 years ago, and seems to be where I am heading. There is internal consistency.
  7. Be open to changing your opinions. Thinking requires flexible opinions.

Resource entanglement problems and the problem of elegance

Category : Games, Meta-Thinking, Productivity, Rationality · No Comments · by Sep 22nd, 2015

I have a problem for you:

Suppose we want to maximize our combined number of X and Y products over 10 days, and each day we can either:

  • Get 3 copies of X if Y<7, otherwise get 4 copies of X.
  • Get 2 copies of Y if X<5, otherwise get 3 copies of Y.

Over 10 days, how should we structure our choice to obtain the maximum number for X + Y?

If you have a strategy bent, then this problem will be a bit of fun, and a bit more complex than it seems at first. This is a type of problem that strategy and resource management games depend on often – when multiple resources have growth patterns that are co-dependent, simple rules can give rise to unexpectedly nuanced problems. Even better, the formula is pretty modular and simple to tweak, so it’s easy to introduce variations.

I call these type of problems resource entanglement problems, since their hallmark is multiple valuable resources with co-dependent growth curves. This type of problem rely on straightforward goals and rules to attract new players and keep those players with unexpected depth. The high ratio between depth and complexity of rules is a hallmark of good game design.

But I’m not here today to talk about game design.


These  problems are not always hypothetical. Resource management is a real field of study, and even outside of business there’s plenty of tradeoffs in everyday life. Consider a classic: time vs. money. With money, we can purchase services to save time. With time, we can put additional effort into making money. Since we value both time and money, we find ourselves in an intriguing cycle.

But there is a trap. Elegant optimization problems are fun to think about, but elegance does not correlate with necessity. Elegant problems grabs our attention but may distract us from more important problems. For example, resource management problems are often much more trivial when the ultimate value of one resource is removed. What if hypothetically, we were to demote our value of money? How much does money mean? What about time? These problems risk sounding senseless initially, but depending on the person may have surprising answers.

If you find yourself working on some intricate problem, perhaps the first thing to ask is what you can demote.

Unity 2D Tips and Tricks

Category : Coding, Design, Games, Productivity · No Comments · by May 28th, 2015

While the 2D features in Unity3D gets a lot less love than the rest of the engine, Unity3D is still a very powerful tool for rapid prototyping in 2D given some customization. Since the 2D features leverage design decision catered toward 3D, there are occasional gotchas in 2D as well to be aware of. Here I detail some of the tricks and gotchas I noticed while working with 2D in Unity.

In general, it is a VERY GOOD IDEA to extend the given MonoBehavior class to create shortcuts for verbose but necessary instructions. The shortcuts can be implemented by way of C# properties. This reduces clutter in code and leads to less bugs. In fact, all but one of the “tricks” uses this to simplify 2D programming.

1. Barring very special cases, most of your objects are going to have the SpriteRenderer component. When extending MonoBehavior, you can implement a shortcut to access spriteRenderer:

private SpriteRenderer _spriteRenderer;
public SpriteRenderer spriteRenderer{
		if(_spriteRenderer == null){
			_spriteRenderer = GetComponent();
		return _spriteRenderer;

The _spriteRenderer in this code caches the spriteRenderer to skip extraneous costly GetComponent calls.
Now, monoExtendedObj.GetComponent() can essentially be replaced with monoExtendedObj.spriteRenderer.

2. Angle manipulation in 2D is usually limited to rotation on the Z axis. However, to specify Z rotation you must go through Quaternions, which are necessary for 3D rotations. We can shove the messy quaternion operations under the rug by defining a custom “angle” property:

public float angle {
	set {
		Quaternion rotation = Quaternion.identity;
		rotation.eulerAngles = new Vector3(0, 0, value);
		transform.rotation = rotation;
	get {
		return transform.rotation.eulerAngles.z;

Note that when getting a value from this property, you will always obtain a value between 0f and 360f. If this is undesirable, consider defining a private variable that stores the non-moded angle value.

3. Alpha (opaqueness) values require dealing with colors property of the spriteRenderer – an extremely verbose operation even with the existing spriteRenderer shortcut. This property lets you set transparency of the spriteRenderer easily

public float alpha {
	set {
		if(spriteRenderer != null){
			Color _color = spriteRenderer.color;
			spriteRenderer.color = new Color(_color.r, _color.g, _color.b, value);
	get {
		if(spriteRenderer != null){
			return spriteRenderer.color.a;
		else return 0;

An alpha value of 1 or more is fully opaque; 0 or less is fully transparent. The values are not clamped between getting and setting so that the alpha may double as a transparency counter/timer. However you might want to use a Tweener to achieve timing effects more gracefully.

1. Most graphic bugs from your 2D game will come from drawing order or faulty z-values. Unity3D’s ordering scheme for 2D sprites is versatile but also confusing. The determining factors for sprite ordering are (from highest to lowest priority):
-Sorting Layers (Bottom ones in the Unity UI are drawn on top)
-Order in Layer (Higher orders are drawn on top, negative values are possible)
-Z value (Closer in camera line-of-sight (LoS) drawn on top)

By default, the camera is at a height of 10 with LoS pointing downward. This implies that without changing the camera, higher Z values are drawn on top. HOWEVER, the camera also has a near-clipping plane of 0.3, meaning that it will not see anything closer than 0.3 units away from the plane perpendicular to the camera LoS (using default values, any Z-value > 9.7).

Finally, note that Order in Layer is a signed short ranging from -32,768 to 32,767. Attempts to utilize numbers outside of this range will likely mess up your drawing order.

There are several takeaways from this. The first is that you should be careful with modifying default camera values unless you are certain about how camera works in 2D. The next is that while working with dynamic Order in Layer and/or Z values are convenient, you will be working with their respective constraints. In general, Z values are better for handling cases where many more layer values than 64,000 are needed (this does occasionally happen), but can cause sprite to disappear if you are not careful. Z value is also a float, so keep rounding errors in mind.

2. Unity3D’s particle and trail renderers do not have their “sorting layer” field exposed, and that’s terrible because suddenly you cannot control the drawing order of your particles and trails.
To fix this, write a custom component that has the below code and attach to your particle or trail renderer:

void Start () {
        //Change Foreground to the layer you want it to display a particle
        //system on, otherwise particles will not show up.
        GetComponent().GetComponent().sortingLayerName = "YOUR_LAYER_NAME";

Note that this will set your object’s drawing layer to a static layer called “YOUR_LAYER_NAME”. If this is not your wish, or you prefer to select the drawing layer in the Unity3D UI, check here to obtain a list of drawing layers and work from there.

3. As these reddit users have found, Unity3D’s 2D collision detection system will make your life very tough if you do not use physics. This is problematic for a lot of simple 2d games where physics would either be a overkill or make debugging difficult.

I have found that the 3D collision detection system has much less stringent requirements. You must still have at least one rigidbody per collision detection, but if you tightly control the z values of your objects (usually by clamping it to 0), you can get around a lot of weird issues that arises in 2D collision detection without physics.

Note that doing both this and ordering with Z value can get hairy fast. Avoid one or the other.

4. Often it is useful to know the dimensions of the sprite either at import time or after stretching, the variables below have very similar names, but only some will be correct:

SpriteRenderer.sprite.rect will specify the size of the sprite in pixels.
SpriteRenderer.sprite.bounds.size will provide the rectangle bounding box of your sprite before scaling in game units. The size of this bound is usually SpriteRenderer.sprite.rect divided by it’s “pixel per unit” under the sprite import settings.
SpriteRenderer.bounds.size will provide a rectangle bounding box of your (sprite)render as it appear in the game, which means after stretching SpriteRenderer.sprite.bounds.size through transforms.

All .size can be replaced by .extents to obtain a box with each dimension halved, this is a useful shortcut when only the size of half the bound box is required.

These are all I have regarding 2D, for now! I’m planning on starting a general Unity3D tips and tricks post soon, and most of that post will apply to 2D as well, so stay tuned!