This fantastic sculpture by Clayton Boyer will delight, amaze, hypnotize, and/or induce motion sickness. He's posted the plans for sale and you can see how others have interpreted his basic design in this Flickr pool! Boyer writes:
This is Zinnia, a spring driven kinetic sculpture that will quietly run about 40 minutes on a full wind. Each of the two display wheels is 24" (61cm) in diameter, and as they change rotational speed and direction they create a variety of visually interesting shapes within the sculpture ~ as well as the contrasting shadows it projects against the wall behind. This is a very easy project to build and a great place to begin your kinetic sculpture and clock making journey. Zinnia's included wheel design is only one example of display wheel possiblities; you can create your own designs! The basic motive mechanism of the Zinnia will easily accept a wide variety of other display wheel sizes, shapes and forms. The possibilities for other variations in display wheel shapes is only limited by your imagination!