But you guys keep missing the point: computer graphics is _not_ 3d.
It's all 2d _projections_ of stuff. Just because you can't build a 3d
model of many Escher works, does _not_ mean you can't create
continuously moving 2d perspective illusions which resemble his works.
There is probably a mathematically correct way to do this. Even if
there isn't, it can probably be simulated through extra processing of
the viewer's perspective as he/she moves. So you run out of illusion
after traversing 180 degrees or whatever. Big deal, you can always
put up a wall to block the user from moving any farther than that.
I suggest that you Escher guys dig deeper on this one. Read some
books on perspective tricks, and apply some savvy about computer
graphics transformations. Deal with the issues head-on; nobody has
_proven_ that it cannot be done. I'd do it myself, but as you well
know, I'm too into Surrealism at present. If you wait on me to "put
up or shut up," you will be waiting awhile. :-)
Cheers,
Brandon