10 most difficult optical illusions riddles A list of optical illusions related questions that are most often answered incorrectly Technology quiz Which of the lines on the right, is the continuation of the black line on the left?Red one. This is known as Poggendorff illusion, first described in 1860. Many detailed studies of the illusion point to its principal cause: acute angles in the figure are seen by viewers as expanded.hard 46% red onered one46%blue oneblue one22%none of themnone of them18%both of themboth of them11%Created by: globalquiz.org. Statistics based on 7164 answers in 4 languages »illusions riddles » Which continent is that?Africa. This map of Africa is rotated so the continent shape resembles Australia.hard 47% AustraliaAustralia45%AsiaAsia4%AfricaAfrica47%North AmericaNorth America2%Created by: globalquiz.org. Statistics based on 12105 answers in 3 languages »continents riddles » Which shape is larger?None of them. Both shapes are the same, but the bottom one is placed more to the right. This is however difficult to notice. It is known as Jastrow Illusion.average 61% AA3%BB21%None of themNone of them61%Both are largerBoth are larger14%Created by: globalquiz.org. Statistics based on 18692 answers in 4 languages »geometry riddles » Which area is brighter?Both are the same. This is the well known checker shadow illusion, first published in 1995 by Edward H. Adelson, Professor of Vision Science at MIT. The area A appears darker because of its light surrounding. At the same time, area B, surrounded with dark areas, appear lighter.average 69% AA9%BB14%Both are the sameBoth are the same69%It depends on the order of seeingIt depends on the order of seeing6%Created by: globalquiz.org. Statistics based on 11886 answers in 4 languages »optics riddles » Which lines are parallel?Green, blue and red. This is a well known Zöllner illusion, first described in 1860. It may be caused by this impression of depth. The black lines are parallel, too!average 69% blue and red onlyblue and red only4%green and red onlygreen and red only9%green, blue and redgreen, blue and red69%nonenone15%Created by: globalquiz.org. Statistics based on 11277 answers in 2 languages »technology riddles » Which continent is that?Australia. This is Australia map, with north at the bottom side.easy 70% North AmericaNorth America10%South AmericaSouth America3%AsiaAsia14%AustraliaAustralia70%Created by: globalquiz.org. Statistics based on 16643 answers in 2 languages »map riddles » How is this polygon called? (the one over the circles)Square. In this Ehrenstein illusion the sides of a square placed inside a pattern of concentric circles take an apparent curved shape. But in reality, the sides are straight.easy 74% squaresquare74%rhomboidrhomboid10%concave squareconcave square8%concave rhomboidconcave rhomboid5%Created by: Debbie Fox. Statistics based on 20150 answers in 2 languages »mathematics riddles » Whose face has been combined with Albert Einstein in this hybrid image?Marylin Monroe. A Hybrid Image is an optical illusion developed at MIT in which an image can be interpreted in one of two different ways depending on viewing distance. In order to see Marylin clearly, you need to move away of the screeneasy 77% Kim BasingerKim Basinger2%MadonnaMadonna7%Marylin MonroeMarylin Monroe77%Woody AllenWoody Allen12%Created by: Cleo. Statistics based on 12473 answers in 4 languages »technology riddles » Which line is the longest?All are the same. This illusion has a long research history. It seems that people living in urbanized areas perceive the lines as representing the corners of rectilinear objects viewed in perspective, being more susceptible to illusion than people from rural areas.very easy 85% AA2%BB9%CC1%All are the sameAll are the same85%Created by: globalquiz.org. Statistics based on 12595 answers in 2 languages »technology riddles » Which orange circle is larger?Both are the same size. This is known Ebbinghaus illusion. Although commonly thought of as an illusion of size, recent work suggests that the critical factor in the illusion is not the size, but the distance of the surrounding circles. In a similar way, the Moon appears larger on clear sky when it's close to the horizon line.very easy 86% the one on the leftthe one on the left2%the one on the rightthe one on the right8%both are the same sizeboth are the same size86%the first one you look atthe first one you look at2%Created by: globalquiz.org. Statistics based on 13338 answers in 2 languages »technology riddles » Play technology quiz and see all the questions.