Consider the 8 × 5 grid shown in Fig. 1.13. How many different rectangles (with integer-co...

Consider the 8 × 5 grid shown in Fig. 1.13. How many different rectangles (with integer-coordinate corners) does this grid contain? [For example, there is a rectangle (square) with corners (1, 1), (2, 1), (2, 2), (1, 2), a second rectangle with corners (3,2), (4, 2), (4, 4), (3, 4), and a third with corners (5,0), (7, 0), (7, 3) (5, 3).]