Inspired by Andres Amador's sandy beach patterns and Simon Beck's snowy footprints, I made a little mandala drawing tool.
The highlight of the tool is that you can paint with it "like in a kaleidoscope": Every brush stroke is immediately mirrored x-fold and the symmetrical structures of the mandala become visible in an instant.
Try online: Mandala-Paint
WARNING - mandala drawing can be addictive...
A few examples:
The tool is based on HTML5 and Javascript.