This first was a test of custom brushes for Krita.
The second shown here, which explores how different kinds of color blindness may be in the perception of those who suffer that, evolved from an attempt to make all of the hues appear as the same shade of gray when desaturated (wondering just how much saturation and desaturation can hide and reveal), which led to wondering about color blindness.
I also used it in a flat-mapped texture across a 3D noise terrain in 3ds Max, of which the following are examples.
I've made hundreds of these, and not yet posted them. [Edit 2015-06-28 naming them, and all of my art, is a computer science project. I've written the naming scripts, and I may soon upload so much art.] I think this could be a procedurally painted cave wall, an alien terrain height map generator, or whatever. You can shift the hues in them all by an equal amount and get wildly different color results. Desaturate them, and you have a relatively uniform black/white/gray mountain height/whatever map that you can use e.g. as random opacity maps in abstract art. You can mix them up in abstract art, smear the colors around, and get freaky cool stuff.