Relative Height

My psychology professor lectured about a concept called relative height. To illustrate the concept, the professor showed the class a sidewalk chalk drawing of a girl swimming in a pool. her leg was sticking up out of the water. From one side of the drawing, it looked perfectly proportioned, but from the other side, the girl's leg looked 3 times longer than the girl herself. The artist had to draw the leg that long in order for it to look correctly proportioned when the picture was viewed from the other side of the sidewalk where the picture appears right-side-up. These pictures made me think about all of the strange ways that artists have to draw things in order for their artworks to look the way they want them to when viewed from the intended angle.