4D Monkey Dust
Henry Segerman shows us shadows (and dust) from the fourth dimension!
Dr Segerman is an assistant professor in the Department of Mathematics at Oklahoma State University.
More Numberphile with him: http://bit.ly/Segerman_Videos
Polytopes in the fourth dimension on Numberphile: https://youtu.be/2s4TqVAbfz4
Henry's website: http://www.segerman.org
(this includes his book, an online version of the monkey animations, and links to buy and print the models he demonstrates)
Discuss this video on Brady's subreddit: https://redd.it/6heiut
This video was filmed during a visit by Henry to the Mathematical Sciences Research Institute (MSRI), which supports Numberphile: http://bit.ly/MSRINumberphile