I found this link, https://peerj.com/articles/19/ whilst perusing Nat Torkington’s Four Short Links. Granted, it’s way beyond my usual wondering, “How do dey do dat?” But if you’re interested in a lot more detail on the Cups and Balls trick? Here ya’ go!
Understanding why the magic works with Penn & Teller
Posted by mentalkibble on March 7, 2013