Look properly at the one who hasn’t been seen entering but has always been there.

Look again at the one who has been seen inside but hasn’t been seen entering.

Look once more at the one who has been inside but doesn’t have a map.

Look once more - and you will find the one who knows everything.

In 2006, I made an impulse decision to buy two resin statues of Magic: the Gathering characters. One was of Eight-and-a-Half-Tails and another was of the Kodama of the North Tree.

While I’m not gonna post photos of them, since they’re no longer out on show like they used to be in my Arrow apartment, and they were pretty stupid purchases since nobody I knew appreciated them. Anyone who knows me also knows that I’m pretty bad at controlling my spending. I buy loads of random stuff on a whim, and it’s usually worked for me.

I tend to think a lot when buying stuff, and this is one of the two really impulse purchases I’ve ever made. The other one is a story for another day. So, like always, I bring back some bulky box into my small Arrow apartment, stuff them into the storage (my apartment was a corner, so it had a small storage space). Anyway, I took them both out to examine. I found one of them lightly damaged, nothing I couldn’t fix - so I put up the other one with a view to alternate every once in a while.

Needless to say, having a fox on somewhat of a stage/pedestal that looks like some kind of extravagant deity in addition to my already slightly strange behaviour - led to my housemate asking me whether or not I pray to the thing. And he wasn’t kidding. *sweat*

After moving to my new place, I didn’t display either since I didn’t have the table space for them. (Arrow had these low drawers that I couldn’t really do much with, so I just put the resin statue on one of them.)

Well, so here, there are in storage and not doing anything at all! Cool eh? Well - at least no one will think I pray to a nine-tailed fox deity and a monstrous looking forest spirit - right?

Of course, I looked at a simplified version of the first part of the problem. There are always more traffic lights in real life. Here’s the big picture (and the real problem):

Now that you know the big picture - does my original argument still hold? To see whether it does, let us consider what happens when we choose to cross at the first traffic light if it is green.

If we do, our problem is simplified to this:

Using our original assumptions of independent Bernoulli trials, you can see simply that you have a 87.5% chance of being able to cross at one of these set of the moment you come to one. This are significantly better odds than you had before (50%) - but it is still unable to beat the result from skipping that first green traffic light (100%). (Yes, crossing at that north T junction vertically DOES NOT require you to wait for a traffic light.)

Surely, there must be a point to me writing about this. The point is simple:

Minimize the number of traffic lights you have to cross
to minimize travel time.

Why is this important? It will help you understand some decisions you can choose to make during my journey to university when I get to that - and the path I chose to minimize travel time, while minimizing disutility while travelling to university. Next up: why you might decide against lower travel time.

I remember have this strange theory that is usually true. I might have even mentioned it on this blog before maybe even blogged about, but this is a post entirely devoted to this funny subject.

In a contracted form, it simply says this: The more coins or small change you have, the more likely you are to give them out - and the less likely you are to receive them. I call it “coin pressure” as a reference to air pressure. Air flows from high pressure areas to low pressure areas - and so do coins. This is typically the case when you go out with friends.

Imagine the case where you go out with friends to eat. Being students, going Dutch is standard practice. There is no arguing over who pays the bill. Everyone pays the bill. Now, some places do cater to students and allow you to pay separately for items on the bill. This means that there is conversation going: “You owe this much from that, and you’re supposed to pay for that, and I’m supposed to pay for this.”

Usually you relegate this calculation to the accounting major students by just using the excuse that usually goes: “Let’s give this to the accounting majors to sort out.” In real life, there’s probably a better mental mathematician at the table than the accountants (in fact I think in our case it was a management major student) - but hey, anything to not do the work.

After it gets sorted out, then everybody gets the numbers. Sometimes the numbers can get pretty bad change wise, for example, $8.90 per person. That means to pay exactly, you need one $5 note, one $2 coin, one $1 coin, one 50c coin, and two 20c coin - and that’s already the simplest possible. 6 pieces of change to pay off your bill.

Of course, if you have the change, you just pay your part. If you don’t, you take on more and more change - in general, the bigger the currency note you have to pay with, the more change you will have to carry when you leave. It follows that the opposite holds true, the more small change you have, the less small change you will have to carry when you leave. (Hence, the origin of the law.)

There is the largest possible denomination of currency - a credit card. If you are paying the bill on behalf of the table by credit card, then you effectively collect all the payment by everyone else - since you had the lowest “coin pressure”.

Of course, there is such a thing as too much coin pressure. If you carry around 200 5c coins just so that you will always have enough coin pressure to pay off any possible bill within $10 - nobody will want to have to split a bill with you.

Moral of the story?

Carry a good variety of coins and small notes with you.

Try to never leave any coins at home unless it’s in your piggy bank. Coins at home have this bad habit of accumulating to ridiculous numbers since you leave more and more and home - and leaving coins at home reduces your coin pressure, hence increasing the probability of you receiving even more coins.