It’s amazing how fast things have dried out now that it has finally stopped raining almost every day. The hostas are getting their usual drier darker shinier late-summer look to them.

I gather hostas are edible: the leaves come up in the spring as tightly furled spears, and you cut them off and eat them like asparagus? I’ve seen some people saying that while there are eating varieties that have particularly good flavon, the usual ornamentals aren’t bad either. But there’s only about a two-day window each year before they unfurl into the arching ovate (pointy oval) leaves, and I keep missing it, not remembering that I wanted to try it until it’s too late.

On the first Saturday of the month, I have a couple programmer friends that I (virtually) hang out with and talk gamedev. So I didn’t really do any coding today. There was one interesting math thing that came up: my one friend had prototyped a 2D tower-defense game and the bullets move fairly slowly so he made his turrets lead the enemies so the bullets would actually hit.

And he had come across a method where you aim at the (moving) target, then figure out where the target would be when the bullet reaches where you aimed at, then aim at that and repeat.

And I pointed out that the exact solution (assuming constant speed targets) isn’t that hard: you figure the position of the target (and hence its distance and the bullet’s travel time) as a function of time. Then you solve the resulting quadratic vector equation for the time value when the bullet’s travel time is the same as the time it took the target to reach that point.

And then it belatedly dawned on me that the guess-and-try method is just numerically, iteratively solving that same equation. Newton’s method or whatever. And it’s computationally more expensive but you don’t have to mess with solving the equations, you can just plug in the formulae and loop until you’re close enough.

So that was an interesting conversation.