foreshortening/perspective

[fatbottoms]

i'm having difficulty with foreshortening. i understand the basic premise, bigger-closer and smaller-farther away, but i need some reference pictures or sketches that shows me the perspective i'm seeking. i particurlary like the up perspective, where the image is shown from the ground up. can anyone post any links or sketches which show this angle, from the bottom up of a figure?

[Steinmetz]

have a look at this site with the works of M.C. Escher who was the undisputed master of perspective www.mcescher.com