On Fri, 20 Nov 2020 15:08:27 -0000, "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.

And the 'Penrose stairs' (on the subject of steps).

I bet many who live on the upper floors of flats knows just how much
of an illusion it isn't, especially when the lift is out of action.
;-)

Cheers, T i m