Each shape is defined by a series of sequential characters, and a new shape is started as soon as you skip a character in the above list. So the first shape could be defined by the series ‘123456’, then the next shape with ‘89ABCDEF’, the next with ‘HIJKLMNOP’, etc. The simplest method +imageWithASCIIRepresentation:color:shouldAntialias: will draw and fill each shape with the passed color (there is also a block-based method for more options).
The readme describes how drawing with ASCII works:
The basics are, you fill a grid with the ordered markers ... Any other characters are ignored.
If the numbers are sequential, they become a path. If you skip a number, then a new path starts. If a number is repeated twice, it becomes a line. If a number is repeated more than twice, it becomes a circle that fits inside the bounding box of all the points.
This sounds like a potentially hacker-friendly way of generating icons and simple game animations. I imagine it would be pretty easy to use it with effects like gradients and drop shadow.
Maybe there's even some way of extending the principle to something like Monodraw?