kcbin.com

What: Okay, it's obvious that this isn't an optical illusion, but it's an excellent optical effect that adapts really well to the digital age. That being said, if you manage to get a physical one, the tactile experience is really enjoyable! Its inclusion is significant because the kaleidoscope is one of the earliest optical toys. The name was coined by its inventor, David Brewster, in 1815... he was later knighted for his work in 1831, so that's Sir David Brewster.

How To: In this version, you can drag and drop an image from your desktop, and it'll appear there! You can also change the number of shards. I think in an ideal situation, I'd have multiple hexagons mirroring, but I couldn't quite figure out the math correctly (I'm not David Brewster). I'll update this if I manage to get it right!

Explain it: Mirrors that are carefully and perfectly positioned.