An enclosed motorized counterweight keeps an artist's whale guts in motion. I used a right-angle drill for a compact form factor and to facilitate mounting. The drill battery powers the arduino, motor controller board and Arduino. A hammer was used as a simple counterweight. Two potentiometers allow the artist to control sway speed and interval. The artist's installation required that the unit be fully self-contained for safety but also permit quick battery changes by gallery attendants. This design also prioritizes easy dissasembly after the exhibit was complete so they can use the hammer and drill in other projects!