An Evolution Simulator.
Artificial lifeforms compete for limited food using genes that are passed on to offspring with random changes
Optimized for run-time efficiency, with speeds faster than 6ms per frame on 10 year old machines
Used by my High School to assist teaching Evolution.
It was the second program I ever wrote that used DirectX (when I was 16!) so it's kind of primitive.
If you'd like to play with the initial settings, Evolution.cpp is the place to go! It uses DirectX 9.0c, which if you're trying to get it to compile will be important :)
Here's a video of with an old voice over:
