The Checkerboard command returns an image of a checkerboard, that is, a grid of alternating light and dark squares.

The optional parameter n specifies the length of each square, in pixels. The default is 20.

The optional parameters height and width specify the height and width of the board, in squares, respectively. The default for height is 8. The default for width is height.

foreground = realcons

Specifies the shade of gray of the foreground color. The default is 1.0 (white).

background = realcons

Specifies the shade of gray of the background color. The default is 0.0 (black).

Other options are passed to Create.