People tend to fear shader code for some reason. This is the little script that runs on the GPU once per primitive, vertex, pixel, or some other driving value (audio sample???). These are all run in parallel, with hundreds or thousands of little workers running the same code just with slightly offset data until it’s all done. When put together, it’s quite impressive what can be done.
Enter Fragment Foundry by Hugh Kennedy. The project’s a little over a year old at this point, but it’s a series of quizzes that are done in WebGL. They provide you with sample code and a GLSL shader editor, and you edit the code on the fly. If you get a parsing error, it will flag the line with a red dot. If you come up with the correct answer, often by changing a single line, it will automatically validate your response.
If you have a few moments, it’s a fun group of brain puzzles, and it’s free.