I don't know if your doctors office/midwives have this first one posted, but it gives you a great idea of what your body does and how much you have to dilate to get that baby out. The second pic is a more realistic pic using common things around your house to really give you a good idea of what a certain amount of cm looks like.
DD#1~Emma Dawn born 12/19/00 7lb 13oz 21"
DD#2~Daphney Mae born 04/17/03 7lb 11oz 21"
DD#3~Grace Deonea born 05/20/10 8lb 2oz 21 1/2"
DS#1~Brody Maxwell born 10/16/13 8lb 10oz 21"