To make the legs on the near side of the Diplodocus, draw a long, oblong shape for the thigh and a rounded rectangle for the shin of the rear leg. Add a rounded triangle on the end for the foot. For the front leg, draw an oval for the shoulder, a rounded rectangle for the upper leg, and another for the lower leg. Don't forget to include the foot at the end of the leg.
We'll add the tail and opposing legs on the next page.