Now reading up on divination through mahjong tiles--a book I've had for years but never really bothered to read until now.

Quite interesting that you can lay numbers 1-9 of each suit in three layers to form magic squares that add up to 15 horizontally, vertically, diagonally, and laterally on each side.

Also quite interesting that if you number all the tiles of three suits from 1-27, you can also create three layers that form magic squares.