This amazing video by CGP Grey starts off as a seeming ode to the metric dimensional wonders of A4 paper and all of the larger and smaller A-size papers that can be made by simply folding (or unfolding) a sheet. But, then things get seriously mind-expanding as they keep folding and folding that sheet of A4, down to the quantum level and beyond, and then back to the A4, and unfolding it out beyond the known universe.
You'll never look at an A4 piece of paper the same again. Trippy and enlightening.
[Originally posted on Adafruit]