Those are all horizontal cylinder vrs.
Metamorphosis III was the first vr I did and the generator of all this optical/Escher vr-work.


"I see it {Metamorphosis}, other than a childlike association-impulse, also as a surrogate for a film.
Most of all, I’d like to express my metamorphosis and association-mania in an animated film, and strongly believe that the animated film will become an artistic expression of great value for the future, in which thoughts of greater importance will be shown than Snow White or Micky (however, I have absolutely no disdain for those products, on the contrary: admiration for Disney’s talent!). Still, I often dream of the film I would like to make. What an astonishing metamorphosis you would then behold…"
M.C.Escher, 1940
From a letter to Hein’s Gravesande