“Silk” comes courtesy of programmer, Yuri Vishnevsky, as an experiment in “generative art” according to the site. All that you do is draw a line, change the breeze, and let the web do all of the work. It’s like fingerpainting, only with your mouse.
It doesn’t look like you could save your masterpiece, but you can watch an amazing replay of all of the tweaking you did to get it into shape. You can try it out here.