A full version app for iPhone, by Ben Blevins.

Updraw is the ultimate app for drawing on the iPad and iPhone. It lets you design and build all sorts of things, from houses to vehicles to spaceships. And, thanks to its integrated physics engine, it lets you do all that with ease.

Drawing on the iPad and iPhone

With Updraw, you can easily design on the iPad and iPhone with your finger or stylus. Just select the part you want to draw, then choose from one of the various tools: line, arc, circle, polygon, rectangle, ellipse, etc.

You can also use the different shapes to design parts of a vehicle or a building.