a checker board的用法和样例：
- The setting-out of Sapporo City is just like a checker board with the streets running most in the north-south and east-west directions and numbered in an orderly fashion.
- A checker slides orthogonally or diagonally until stopped by an occupied cell or the edge of the board.
- Peter waving a checkered flag as he passes!
- A family with a checkered past .