I saw this lesson at the blog Buggy & Buddy. It was called Gliding Robot Craft. 4th graders took their knowledge of simple machines to use the Engineering Design Process and make an art pulley. The only requirement is that you design a subject that would have movement.
I introduced the students to kinetic art from Calder to modern artist creating moving waves and walking wind machines. How else could you use simple machines to make art?
Tape down 2 straw pieces, one yard of string to feed down through the straws, and tie a bead to each end. then hang is up and pull down and out!