With PATRICK CAVANAGH

Motion undershoot. Bar rotates through 180°, from 12 to 12 o’clock.  But it appears to move only from 1 to 11 o’clock.

Same as the ring but for linear motion. Red and green bars are in the same position but appear to be offset. Try tracking them with your eyes; your eyes feel as if they move, but they really don’t!!

Same idea here! Right-angled cross looks wonky because moving sector edges shift the cross arms more than moving middles of sectors.