Use the arrow keys to move (color trail), space to stamp (stamps, obviously), and the "a" key (color change)
Docs: https://docs.google.com/document/d/1m8ppyD_-g1zxSJ6wfbRvQ3DdVHN__ErCKQ3YjbAXp4E/ OR: http://bit.ly/1wySoIm (both go to the same thing)
