Anamorphic Art for High School Students

I’ve written here before about our annual Sonia Kovalevsky Day at Hood, where we invite local high school girls to campus to learn more about math and careers in STEM in honor of Sonia herself, the first woman to earn a Ph.D. in mathematics. This year I was co-organizing the event and also running one of the workshops. I dithered for way too long about what I wanted to do with the students, but I finally settled on a topic I’ve liked since I was a kid: anamorphic art. We’re often called on to show off our discipline to kids, and I think this is a neat topic that’s cheap to implement and easy to adapt to most grade levels.

The Ambassadors, By Hans Holbein the Younger (1497/1498–1543) – bQEWbLB26MG1LA at Google Cultural Institute, Public Domain,

Anamorphic art refers to art that needs to be viewed from a specific angle or using a specific device like a mirror in order to be seen properly. The classic example is in a painting called The Ambassadors by Holbein, which holds a Halloween-appropriate secret message when seen at the right angle. I put it on the screen and had the students wander around the room until they found the sweet spot.

I showed a few more examples of these types of paintings, both old and new, and talked a little bit about how images can be transformed via different types of grids. Most of them knew about one- and two-point perspective, so they seemed to get how that type of transformation would work.

Then we got to the fun stuff: circular mirror anamorphosis. I passed out a bunch of examples without really explaining anything, and asked them to figure out what was going on. Most of them started bending the pages into a cylinder right away. I gave them small sheets of mylar I’d cut to roll into a cylinder to see the images properly. Mylar comes in a big roll for about $20, and you can find it online or in hydroponic gardening stores. Then they spent awhile looking at a bunch of examples. Some came from an old book of examples from a Victorian toy, now out of print but still widely available. Most I found online in various places, and the most notable examples came from an artist named Istvan Orosz, who makes incredible prints where the mirror reveals a hidden portrait.

Last I had them make their own examples, using pre-made grids I found online. These grids aren’t completely accurate, and someday I’ll probably make my own, but I just didn’t have the time. The students drew their own pictures and transcribed them onto the circular grid, and admired their handiwork in the mirror. Biggest advice for doing these: keep your drawing simple. Pixel art is highly recommended if you’re not artistically inclined.

I finished by talking very briefly about the mathematics behind all this, and gave some applications: painting road signs or logos on sports arenas, snapchat filters, and projection mapping. I showed a couple cool videos of those at the end, while they finished their drawings.

I was worried about hitting the right level with my audience: didn’t want to be too technical, but also didn’t want to dumb it down too much. Also, we only had 45 minutes together, so I couldn’t include everything I wanted. These students aren’t necessarily already math-inclined; in fact we encourage teachers to bring students who don’t think they’re strong mathematically. This was my shot to talk to a bunch of young women about why I love math, and I didn’t want to blow it by either confusing or boring them. Their evaluations of the day aren’t quite processed yet, but I think I hit the sweet spot.