Here are two Macintosh OS X Screen Savers. I have only tested them on my iMac under OS X 10.2, but the price is right. If they work for you, or don't, I'ld like to know.

PileUp

PileUp piles a set of pictures, one by one and one atop another, randomly across the screen. If the pictures are cropped to the object, the screen will look like a pile of those objects, for example autumn leaves.

Download the PileUp screen saver.

PileUp is bundled with a few leaf pictures, but it can use any folder of pictures. I've made a few sets of pictures thay you may want to download as well.

Got ideas for more collections? Got collections that work well? Let me know.

DesktopWorm

Wormy shapes crawl out and eat trails across your desktop. Select the number, length, and squirminess of the worms.

Download the DesktopWorm screen saver.