DESCRIPTION:
This novel animated illusion is based on a static Op Art work by G. Sarcone aptly named “Straight or Not” ( http://www.moillusions.com/straight-or-not-optical-illusion/ ).
The initial optical pattern consists in two concentric checked frames with alternating black and white polka-dots. Though the checked frames are perfectly straight, the overall appearance is a wavy pattern. Actually, the small white and black dots create layouts of ‘subliminal’ oblique lines, which interfere with the orthogonal outlines of the frames creating the bulging illusion. If you observe the static picture with half-closed eyes, you can perceive these ‘subliminal’ oblique lines. This optical effect is related to Zöllner illusion.
So, we wondered what would happen if we move and invert the position of the dots in a continuous loop? What we discovered is that the wavy effect not only does not disappear, but generate an undulating counter-effect: the frames appear in fact to wave back and forth. The viewer can see that ONLY the small dots are moving and cause the concentric checked frames to appear to wobble continuously.