This application was uploaded about 2 weeks ago. It takes RGB Color values, from 0-255, and creates collapsing/exapnding circles based on that color.
If you set it up like the image above, you will set it to red:
Of course, if you set blue to 255, you will get a blue circle, and green at 255, will give you a green circle. Dragging on the screen from left to right will increase its speed, and dragging right to left will decrease it and change it from expanding to collapsing.