January 22, 2018 at 03:29AM

Today I learned: 1) I kind of knew this from experience, but Andrey Shur confirmed for me today that it's rare to find a 2 amp USB phone charger, largely because USB isn't quite rated to carry 2 amps. This is curious, as Raspberry Pis recommend you use a 2 amp charger. As I am learning, Raspberry Pis were made with some really odd design decisions. 2) ...a bit about Hilbert curves. Or, technically, *the* Hilbert curve, which is the limit of pseudo-Hilbert curves of N iterations as N approaches infinity. If you google image search for "Hilbert curve", you'll find a bunch of example pictures, which is going to be much easier than reading me awkwardly try to explain the shape... but in short, a pseudo-Hilbert curve of N iterations is a fractal line that neatly visits every grid point in a square (with side length log2(N)). As you take larger and larger iterations of the pseudo-Hilbert curve, it becomes a denser and denser nest of curves. The cool thing about the Hilbert curve is that, in the infinite limit, it is "space-filling", which means that it eventually visits every single point in the square it's defined over. Essentially, that makes the Hilbert curve a mapping from a line to a plane... which sounds obviously wrong, but is mathematically provable. It turns out that a (the?) key property of the Hilbert curve for analyzing its space-filling-ness is that it's "stable", in the sense that if you follow a point on the pseudo-Hilbert curves as you add more iterations to it, that point will converge to a fixed position, and it's possible to calculate what that position is. That's important, because without this property, the concept of "the curve that this curve approaches as you iterate to infinity" doesn't make sense -- if the mapping of every point doesn't converge, then the curve doesn't really "converge" either. If you'd like to learn more about Hilbert curves, I highly recommend this video, "Hilbert Curve: Is infinite math useful?": https://www.youtube.com/watch?v=3s7h2MHQtxc 3) ...a little bit about screenplay script formatting. Industry screenplays are... weird, coming from someone who has never written one before. For one thing, everything's centered. Scenes open with a description of the scene, usually one sentence, using the whole page width and ALL IN CAPS. Those scene-setup sentences also usually start with "INT." or "EXT." for interior and exterior scenes, respectively. Most of a screenplay is dialogue, of course, and all dialog is written with insanely large margins, so it reads like a little column of text smack in the middle of the page. The name of the speaking character gets its own line. Description of *how* a line is delivered come in the form of parentheticals, which also get their own line, are contained within parentheses, and have about an extra half inch on each margin relative to the actual dialogue. (I didn't say I learned anything about writing a *good* screenplay, just that I learned how to *format* one.)