Baby Perlin shows off Baby X's ability to do small but serious work. Perlin noise is a system for generating images procedurally. You can get a few startling effects, like wood, marble, and clouds, just by setting the right parameters and the right palette. However generally and as a rule the images are not used on their own, they are used in games or other simulation programs to add a bit of randomness and visual complexity to artwork.
And this tool is a very simple way of playing about with parameters and palettes until you get the effect that you want. Perlin noise can also be animated.