Take a look at this short and simple animated #gif showcasing the Jastrow illusion in action! The Jastrow illusion was first discovered in 1889, by American psychologist Joseph Jastrow. In this clip, both figures are identical in size, although the lower one appears to be slightly longer. The short edge of the upper shape is compared to the long side of the lower one. If you still can’t pinpoint what causes this illusion – it’s because the lower object is placed slightly to the right. This isn’t immediately noticed, because both of their edges are skewed, and both are placed along the imaginary line, one parallel to their edges. I’m not sure I managed to explain this properly, so better take a look at this picture below and you’ll understand the cause immediately!