In my beginning art class, we had to do a couple of drawings studying perspective. These were some of the more difficult drawings we did. In quilting, there are techniques used to make the tumbling blocks pattern seem three dimensional by using diamonds instead of cubes and shading with fabric choice. In the first Lord of the Rings movie, extended version, there is a disc describing how using this technique created size differentials between characters when the actors were really similar in height. I loved the pictures where the seat between Frodo and Gandalf in the wagon was about 5 feet apart. By sitting behind Gandalf, Frodo appeared to be half the height of Gandalf. And the other day, I got a photo where Charlie is shrunk to half the size of Sophia.
Now if I had tried to create that photo, it probably would not have happened. If your interested in learning more, check out this wiki page