Why Isn't My Pygame Display Displaying Anything?

I am working on a program that evolves creatures over time using a genetic algorithm. However, for some reason, my pygame display stopped working and I have absolutely no idea why.

Solution 1:

I suspect the livingCreatures variable is never set to False, so the pygame.display.flip() never gets called--and you won't see anything on the screen at all until you flip the buffers. The fact that you're filling the screen with a color, but then still seeing black, is a dead giveaway for this sort of problem.

In the future, you should also try to reproduce the problem in a simpler example without domain-specific, irrelevant code.