Don Shank is a geometry architect from Oakland, California (or so his Blogger profile states), but in his spare time he likes to paint on his iPad.
When I have some spare time (hahahahah) I like to paint on my iPad. Most of the people I know that use an iPad use a stylus because they want to draw/sketch more than paint. Yes, drawing with your finger isn’t so great but I have no problem Painting with my finger. In fact, I like it quite a bit.
He’s apparently using the Brushes app. Check out his site for even more of the fantastic work he’s done.