The Fraser spiral illusion is an optical illusion that was first described by the British psychologist Sir James Fraser (1863 – 1936) in 1908. The illusion is also known as the “False spiral”, or by its original name, the “Twisted cord” illusion. The overlapping dark arc segments appear to form a spiral; however, the arcs are a series of concentric circles.
The visual distortion is produced by combining a regular line pattern (the circles) with misaligned parts (the differently colored strands). Zöllner’s illusion and the café wall illusion are based on a similar principle, like many other visual effects, in which a sequence of tilted elements causes the eye to perceive phantom twists and deviations.
Super soft, stretchy and comfortable yoga leggings.
• 82% polyester/18% spandex
• Material has a four-way stretch, which means fabric stretches and recovers on the cross and lengthwise grains.
• Made with a smooth, comfortable microfiber yarn
• Raised waistband
• Precision-cut and hand-sewn after printing