On 20/11/2020 15:08, Brian Gaff (Sofa) wrote:
Lightening this up, when I was younger and could see there were many optical
illusion pictures around. One was the impossible waterfall, as I'm sure you
have all seen where they all join up and all appear to go downward.
There was another of a one sided ladder that curved and had a twist, so
that the little cartoon men could not only climb forever but never find the
other side.
The old obvious loop. One sided bit of paper etc.
Brain breaking stuff.
Brian

Mobius?

Bill