This is Quads, from Week 4: Control.

This video uses one of the many custom programs I wrote for this course. Here I've written an interactive program for playing with the shapes and looks of 4-sided figures (or quads). The program also shows, at the top, the line of text we'd type to make that shape.

I wrote all of these programs in the same same Processing language that we use in the class, so you can run them yourself on your computer. Even better, since you get every one of these programs, you can open them up, see how they work, and then use bits and pieces of them in your own projects.