david.li/paint is a spectacularly gloopy painting app online. You can set paint fluidity, bristle count and brush size, and of course pick any color you like. What I like about it (as opposed to pro apps like Corel Painter or Artrage that offer similar natural media simulations) is that it’s just a loaded messy brush that doesn’t make it easy or clean itself up for you. The limitations force you to work with it! Author David Li published the source code.
Fluid paint simulation on the web
