collisiondemo

Left click to add a 5star. Right click to add a 7star. Midclick (or shift-click) to add a 9star. Click on a star to remove it.

5stars bounce off of 7stars and cause their collidees to throb in size.

7stars bounce off of 5stars and cause their collidees to spin.

9stars bounce off of everyone else, but don't define their own colliders; they cause their collidees to color shift.

That's all!