Can somebody tell me how to create the effect of the attached where there's a circle with pointed edges in Illustrator CS? I've tried using the triangle tool then pressed up a bunch of times while creating it, but the points are like halfway between the middle and outer edge of the circle. I don't want to points to go in any more than a few pixels.
Also, is there an easy way to place multiple circles on top of each other so their centerpoint is exactly on top of one another? If so, how do I do this?
Any help would be greatly appreciated.