One of the hardest things in drawing and painting is controlling the individual strokes. Not only do you have to control the location but also the pressure, tilt and rotation of the pen or brush. This means mastering five or six degrees of freedom at the same time with extreme precision. Doing it well requires years of practice. Modern painting applications and tools like drawing tablets emulate this experience quite well, but the beauty of computers is that we can do even more.
As an experiment I wrote a test application that separates tilt and pressure from drawing. In this approach one hand draws the shape as before, but the other controls can be controlled with the other hand by using a regular gamepad controller. Here's what it looks like (in case your aggregator strips embedded YouTube players, here is the direct link).
The idea itself is not new, there are discussions about it in e.g. Krita's web forum. Nonetheless it was a fun weekend hack (creating the video actually took longer than writing the app). After playing around with the app for a while this seems like a useful feature for an actual painting application. It is not super ergonomic though, but that may just be an issue with the Logitech gamepad I had. Something like the Wii remote would probably feel smoother, but I don't have one to test.
The code is available here for those who want to try it out.