I just discovered the 20-year-old Wireworld computer, which appears to be just a picture. It's much more than a picture. Its a functional piece of art that calculates prime numbers. It's a description and implementation of a computer. It must have been a labor of love for the folks that created it.
From the picture I learned about one choice for the only instruction in a One-Instruction computer. (Load, in this case. It's very clever.) I also learned a bit about JSL matrix operations, and how to make JSL fast. A Windows computer just spent the last month making a set of bitmaps to turn into a video.