10 most difficult optical illusions riddles A list of optical illusions related questions that are most often answered incorrectly Technology quiz In what process sky colors (including blue sky and red sun) are created?Rayleigh scattering, named after the British physicist Lord Rayleigh (John William Strutt), is an elastic scattering of light or other electromagnetic radiation by particles much smaller than the wavelength of the radiation. very hard 33% iridescenceiridescence11%Rayleigh scatteringRayleigh scattering33%miragemirage12%atmospheric refractionatmospheric refraction42%Created by: Ninjai. Statistics based on 5316 answers in 3 languages »light riddles » 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 45% red onered one45%blue oneblue one20%none of themnone of them20%both of themboth of them13%Created by: globalquiz.org. Statistics based on 13736 answers in 5 languages »illusions riddles » Which continent is that?Africa. This map of Africa is rotated so the continent shape resembles Australia.hard 48% AustraliaAustralia44%AsiaAsia4%AfricaAfrica48%North AmericaNorth America2%Created by: globalquiz.org. Statistics based on 20851 answers in 5 languages »continents riddles » This is a rare phenomenon called iridescent clouds. It occurs in the clouds with ...Small droplets or ice crystals. The effect is similar to irisation. Iridescent clouds are a diffraction phenomenon caused by small water droplets or small ice crystals individually scattering light. Larger ice crystals do not produce iridescence, but can cause halos, a different phenomenon.average 60% volcanic dustsvolcanic dusts13%sulphuric acidsulphuric acid15%detergent vaporsdetergent vapors10%small droplets or ice crystalssmall droplets or ice crystals60%Created by: Tschuka. Statistics based on 19378 answers in 2 languages »sky 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 67% AA2%BB17%None of themNone of them67%Both are largerBoth are larger12%Created by: globalquiz.org. Statistics based on 35959 answers in 5 languages »geometry 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 only8%green, blue and redgreen, blue and red69%nonenone17%Created by: globalquiz.org. Statistics based on 22362 answers in 2 languages »technology 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.easy 72% AA8%BB12%Both are the sameBoth are the same72%It depends on the order of seeingIt depends on the order of seeing6%Created by: globalquiz.org. Statistics based on 20819 answers in 5 languages »optics riddles » Which continent is that?Australia. This is Australia map, with north at the bottom side.easy 72% North AmericaNorth America10%South AmericaSouth America3%AsiaAsia14%AustraliaAustralia72%Created by: globalquiz.org. Statistics based on 31451 answers in 3 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 rhomboid6%Created by: Debbie Fox. Statistics based on 39402 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 78% Kim BasingerKim Basinger2%MadonnaMadonna7%Marylin MonroeMarylin Monroe78%Woody AllenWoody Allen11%Created by: Cleo. Statistics based on 27106 answers in 4 languages »technology riddles » Play technology quiz and see all the questions.