Arduino-based laser turret/automatic cat toy using a pan-tilt rig (https://www.adafruit.com/products/1967) and laser diode (https://www.adafruit.com/products/1054). Random laser path, speed and pauses determined by homebrew Markov chain algorithm.
(The panel text was made using QCAD and then printed (horiztonally reversed) onto transparent inkjet paper).