This program isn't really anything impressive, I just decided to make it because I was feeling bored. You can choose how many squares you want on the screen, and adjust their speed or size (individually when spawning new ones, or collectively). When a square hits the edge of the screen, it changes color and bounces off the edge, which gives mesmerizing patterns with vibrant colors. The version you see in the video is not the final version, as I added a few more features after recording that, but the principle stays the same.