A digital sketch of Albert Einstein specifically done for Illustration Friday's current topic, 'Theory'. Einstein of course being the creator of the theory of relativity.
Below is a video of the sketch done in Painter X. Painter's very useful for this as there's a saveable script which can record all your brushstrokes for playback.
The music is 'Buy me a pony' by Aussie band, Spiderbait. Enjoy!