When I was in college a million years ago, I had a class in Chaos Theory.

The professor knew I worked on sets for the theater group, and he wanted me to build a full-size double pendulum that someone could ride on. I pointed out that it would likely kill the rider, tear itself apart, or both.

Instead I wrote a double pendulum simulator. You could adjust the weights and lengths for each pendulum and the starting position. Run it with the exact same setup and see the exact same result, or make a tiny, tiny change and see the motion was completely different.

I think I still have it somewhere. On a 3.5" floppy disk. Borland TurboPascal.