center water ripple

How would I create a ripple that originates from a center point (like a water drop hitting the water)?

btw, flamingpear.com is an awesome site. I've made better graphics than ever using their tools.

Thanks in advance,

Use the zigzag filter

Heres my edit: Maybe a bit more info for you. I drew a circle, then ran zigzag on it, that will give you what you need to star. play around with shapes with that filter

You can also take an image or graphic and apply the rectangle to polar coordinates filter. Keep applying it and it will look like a closeup of a water ripple.