Is light a wave or a particle... or both? The classic "double slit experiment" using coherent light (i.e. a laser) gives some insight. This design consists of a stand for a laser pointer and a single or double slit gate made of paper or aluminum foil so you can conduct your own double slit experiment. Can you predict what will happen? All you need is the printed parts, a laser pointer and some paper and/or aluminum foil. The printed parts include a stand for the laser pointer, a frame and alligator clip to hold the gate material and a circular clip to hold down the laser pointer button. Print multiple sets of frames and alligator clips and you can quickly switch back and forth between different gates.