barber pole, but no illusion

In this case, the direction perceived seems to always correspond to the true direction, as revealed by the corners when they are unoccluded. So no illusion. In the illusion, the pattern moves diagonally but you perceive it moving vertically due to the shape of the aperture.

[@wolfganghukriede4739]

Good.

[@jjhassyGAMING]

ok