I was astonished to read about a Japanese artist who uses the 3½" screen of an Apple iPod Touch as his canvas, along with a $2.99 app, ArtStudio, to produce some amazing pictures. The Telegraph reports that Seikou Yamaoka took about 3½ hours to produce the image shown below, creating it during his train journey to work.
Here's a speeded-up video showing how he did it.
That's amazing! You can see more of his creations in an online picture gallery at the Telegraph, and more videos on YouTube showing him at work. He also has a Facebook page.