The Mandalas are geometric designs symbolic of the universe.
Coloring these shapes you can get a relaxing effect.
You'll find various models on
Interestingly, in a dynamic format the effect
can be more stimulating than relaxing.
maximum impact of black and white on a simple grid.
For best results, you can watch in a dark room.
Pandora Visualizer from Ross McCampbell on Vimeo.
Finally you can try to invent your own designs.
You can design from concentric circles or squares.