Stones on an Infinite Chessboard - Numberphile
16:07
Terrific Toothpick Patterns - Numberphile
9:46
How many ways can circles overlap? - Numberphile
32:17
The almost impossible chessboard puzzle
13:48
Dungeon Numbers - Numberphile
18:48
The Unlikeliness of Numbers Sharing Factors
18:42
O quebra-cabeça impossível do tabuleiro de xadrez
21:12
The Infinite Pattern That Never Repeats
23:38