I really love the Stereo Rhythmicon patch from Critter & Guitari, but I missed some features. As I wanted to learn Pd anyway, I thought it would be a good idea to start by modifying this patch. The most important new feature is, that an overtone can now be stopped by pressing the corresponding key again.
You can find the patch (and a list of all changes) here
Now I start to work on my first own patch, so please wish me luck