A Small Checkerboard

Draw a board of 4 rows and 4 columns of squares, each with sides of 40, touching each other with no gaps. The turtle starts in the center, facing right, at the bottom-left corner of the board, so the board is above and to the right of that point and is 160 wide and 160 tall.

Every square has a black outline. The bottom-left square is filled black, and the fills alternate like a chessboard: counting rows from 0 at the bottom and columns from 0 at the left, a square is filled black when its row number plus its column number is even. The other squares have no fill.