A couple of mirrors, a cardboard tube, and a bunch of random crap. That’s what’s behind the mind-twisting magic of a kaleidoscope. And when we say random crap, we literally mean that. There’s no real method for designing the end cap of a kaleidoscope, they just add whatever they want. Some objects are glued down, some are left to float, and the results all look totally crazy because of the triangle mirror system.
The mirrors are set at 60 degree angles to each other which reveal basically limitless reflections when you look down the tube.
source: gizmodo.com by Casey Chan