The Phistomephel Ring
Simon Anthony (from Cracking the Cryptic) reveals the Phistomephel Ring - a hidden feature of ALL Sudoku puzzles.
Second video is here: https://youtu.be/h8AulgkjyIc
Cracking the Cryptic: https://www.youtube.com/c/CrackingTheCryptic
Another Numberphile video about Sudoku: https://youtu.be/MlyTq-xVkQE
Our thanks also to the legendary Phistomephel.
