As a nightmare in the opposite direction, I've been writing a new pathfinding system for Second Life, from the user side. Where you get a maximum of 64KB per program. KB. Not MB. And that's for code, stack, and data, using the Mono engine.

You can have many programs, and they can pass messages around, so you can do jobs that won't fit in one program. It's like coding for a cluster of Arduinos.

I've had to pack data into integers with shift operations. Come up with an efficient maze solving algorithm that only needs 2 bits per cell. Divide tasks into multi-step pipelines. Monitor memory usage and divide the data into smaller chunks that will fit. Plus it's soft real time and has to run properly under overload conditions when it can't get enough CPU time.

It's kind of neat to see autonomous characters running around the virtual world at running speed. This was believed to be impossible, but I got it working out of sheer stubbornness. It was far too much work.

(Second Life has a built-in pathfinding system. It's too buggy to use, and they refuse to fix it. This is a workaround.) (Why such tiny programs? Because they are not only persistent, for years if necessary, but are copied from one machine to another, state and all, as objects move around.)