Whenever and wherever inspiration strikes you, [[xref:http://www.pcworld.com/appguide/app.html?id=86540|Brushes|Brushes]]can come in handy. With this app you can go beyond doodling, using realistic brushes and virtually any color you want. Better than paper, Brushes offers deep undo and redo.
Amazingly, artist Jorge Colombo used Brushes to draw the June 1, 2009, [[xref:http://www.newyorker.com/online/blogs/tny/2009/05/jorge-colombo-iphone-cover.html|cover of The New Yorker|Cover Story: Finger Painting]] while standing for an hour outside Madame Tussaud’s Wax Museum in Times Square.
A companion for this app, [[xref:http://brushesapp.com/viewer/|Brushes Viewer|Brushes Viewer]] (Mac only, free), allows you to replay your Brushes painting stroke by stroke.