This post is not a direct answer to your question, but rather a movie recommendation.
"Dimensions" try to help you visualize the 4th dimension by projecting it onto the familiar two and three dimensions. It also contains a part depicting two-dimensional beings trying to conceive of a third dimension, so that the viewer can visualize the easier and analogous situation first.
The graphics are pretty and it is totally free, but it never suggests anything else than the stereograpic and orthogonal projection. Check it out!
