I have a pen plotter! I bought it on eBay, broken, and spent the difference fixing it. Now my favorite thing is making holograms. Inspired by William Beaty's hand-drawn holograms, I use the plotter to etch reflective ridges on CD jewel cases.

The curvature of ridges controls the movement of highlights, creating depth. I tried other materials like plastic sheets and waxed paper, but CD jewel cases worked best. The results are magical in person.

The light must be a point source. These are holographic in that small cutouts retain the scene. I think ancient peoples could have done this.

It's neat.