There is a new version of GearSketch, written in CoffeeScript. This means GearSketch now runs not just on your pc, but also on your tablet or smartphone. Check it out at gearsket.ch
This version of GearSketch is open source, released under the MIT license. If you speak CoffeeScript and want to change or add something to GearSketch, you can find the source code at: github.com/frankleenaars/gearsketch