This program makes self-similar images. I was originally inclined to call the images it makes ‘fractals’, but then someone gave me the actual definition of a fractal (a set with fractional dimension or something). I realized the images it makes aren’t quite like that.

As input to the program, you give a definition of the desired image's self-similarity. The image can ‘contain’ direct, flipped, scaled, or rotated copies of itself. You define a number of mappings from two vectors to three, where you give each of the three as a linear combination of the two. Here is one possibility:

In this case, the image contains two copies of itself: one that is rotated 45 degrees clockwise and scaled a bit, and one that is moved up the y axis and scaled more. To communicate this possibility to my program, you give it this on stdin:

This results in the following image:

The program was inspired by the visprint program written by Ian Goldberg, which was in turn based on an idea by Hal Finney. I thought the images produced by visprint were very appealing, so I wanted to mess with the code. Unfortunately, I could not seem to decipher the code, so I wrote my own program from scratch.

News Flash!
I just discovered that Pete Keller (I know this guy due to the Condor project and the UPL) has made a program similar to this that is vastly cooler! It makes images that are essentially similar to the ones my program makes, but it makes them in three dimensions using OpenGL and animates them in real time! Here is his code.