On Sun, 03 Oct 2010 11:02:32 -0700, Smitty Two
wrote:
Easy enough to test this with some dark and light fabric or painted
cardboard, etc. taped to the steps. Even the fancy colored "electrical"
tape could be used for some rough experimentation.

Hmm. That's probably within my capabilities. ;-)

I can
imagine optical illusions arising from loss of depth perception, leading
to an unfortunate misinterpretation of visual cues you intended to be
helpful.

Exactly my concern.

Edward