Thanks, Bill. It's great to see someone else working through the same sort of logical processes I struggle with. smile

Perhaps I can best explain my difficulty using your balloon analogy. It works because, as you pointed out, the third dimension is there all the time. However, in a genuinely 2D situation the the extent of the third dimension is zero. The only 2D thing I can think of is a shadow. Now I try folding the shadow, and that is where I run into trouble.

There never was nothing.