8 x 16 , 15 x 30 , 20 x 40
5 x 7 , 8 x 10 , 11 x 14 , 16 x 20 , 24 x 30, 30 x 40
4 x 6 , 5 x 7 , 8 x 12 , 11 x 14 , 24 x 36
