Checkers (or Something Like It)

Following the class example of making a button in Processing, write a Processing program to draw a chessboard / checkers board. These boards are typically drawn in black and white, but you can choose any combination of dark and light colors. When you click on a square, the program should draw a colored circle centerred in the square you clicked on (choose a different fill color for the circle from what you used for the dark and light squares).