These are some repeating patterns and textures I made with code (and a tool that I made (with code)). Some of them aren't seamless because I hadn't worked out all the kinks in my implementation of a wrapping canvas. I also only have the code to reproduce a few of these.
I've since started a project called Pixel Weaver that allows for more types of doodles (3D, anyone?), gives control over time, all while saving reproducible programs in every exported screenshot.