The human brain is a remarkable living machine. It’s constantly processing sensory input and churning away on innumerable little tasks that make up your very being. Humans rely on having a big, powerful brain to solve problems and avoid danger. However, when we encounter a visual input that doesn’t make sense, our brain will do its best to fill in the gaps — it’s just not always right. The result is an optical illusion, and you can experience them from the safety of your internet connection. Click the gallery to see each one of the pics and then check out the full explanations of each animations below, without your browser being weighed down by all those hefty GIFs!The Phantom Green DotTo get this illusion to work, just stare at the center of the image. As the pink dots swirl around, the gap will quickly be replaced by a green dot. I can assure you there is no green in this GIF — try following the gap’s movement with your eyes. The green dot is gone, right? This is a result of how the eye perceives color, as described by the opponent process theory. The photoreceptor cells in the retina that see the magenta dots quickly become saturated and tire out, so you see an afterimage of the magenta dots. The weakened signal is interpreted by your brain as the opposite color, the antagonist of magenta, green.The Spinning DancerThis one will really mess you up. The spinning dancer illusion was designed in 2003 and has been melting brains ever since. The silhouette of the dancer lacks all depth cues, so your brain interprets the movement as either clockwise or counterclockwise. It seems most people get clockwise at first, though. Now look away or down at her foot. In a flash, the direction seems to have reversed. When you’re watching the rotation, whichever way it’s going seems like it must be the right one. How could it have ever been different? Then it changes again and your brain explodes with “whaaaaaaa?”Flashed Face DistortionThe flashed face distortion effect is likely related to the brain’s strong drive to spot and recognize faces. We want to differentiate between the two faces, but there isn’t enough time. When you look at the center of the image, your peripheral vision picks up on the presence of the faces, but your brain lacks the data to fully process them. What you get is a bizarre caricature of the real face. A person with a large nose appears to have a gigantic schnoz and someone with a slightly asymmetrical face looks like Quasimodo. Brains are weird.Motion-induced BlindnessThis GIF is interesting not only because things literally disappear from your vision, but because we don’t know exactly why it happens yet. Stare at the middle and the yellow dots blink out. Look to the side, and they come back. Science is still trying to nail down the exact cause, but there are several good hypotheses. It may be a case of your brain filling in the peripheral vision incorrectly because it is overwhelmed by the spinning motion. Alternatively, it could be an adaptive strategy to facilitate better perception of movement. Whatever causes it, it’s cool.Gathering For Gardner Dragon The human brain, as previously mentioned, is programmed to recognize faces. Even faces that don’t look entirely human can be favored in an ocean of stimuli. The GIF above shows how the Gathering For Gardner dragon (named after science writer Martin Gardner) seems to follow the viewer around the room. The brain sees the features of a face and processes it as a regular convex surface. It’s actually concave, but the brain can’t sort that out until you get around to the side.Illusory SquareThe phantom square connecting the four smaller dots is a result of illusory contours. The same effect happens with some static images, but it’s much more profound in this animation. It is believed illusory contours are generated in the V2 area of the visual cortex, which is responsible for processing complex shapes. It’s simply thrown off by the moving dots and the intersection of the larger dots with the square in the background. The result is that the smaller dots are perceived as the corners of a square.Floating CubeThis illusion packs in a few visual quirks to trick your brain into thinking the object is a floating 3D box. Your brain wants things to be regular three dimensional shapes, so the lines and surfaces in this concave box are processed as cube. That background also serves to make the shape seem like it has more depth, making the illusion more potent. The brain is really just taking a guess based on limited visual information.Inverted ColorThis is another example of opponent process theory causing a negative afterimage. The photoreceptors in your eye are being overwhelmed by the magenta and blue tones. When the image flips to the neutral grayscale version, the weakened signal from those photoreceptors causes the brain to interpret the image as having the opposite, or antagonist color from the magenta and blue channels. That means you see greens and yellows — an almost natural color image.Penrose TriangleThe Penrose triangle was popularized in the 1950s by mathematician Roger Penrose. You can follow the path of the ball around the triangle and it seems to make sense at first, but there’s just something off about it. Any two corners follow normal Euclidean geometry, but that third one is connected in two different planes. The literal Penrose triangle cannot exist in real life.The Growing CigaretteThe trick with this illusion is all in the background. The drawing of the wall makes the brain think it is looking at a 3D scene. Therefore, it assumes one cigarette is farther away than the other. Since in a real 3D space those lines on the wall would be parallel, your brain tells you that one cigarette is clearly larger than the other because it’s farther away and crosses more lines. So when the left one rolls over, it seems to get larger VIEW PHOTO GALLERY The Phantom Green DotThe Phantom Green DotStare at the center and the gap in the pink dots will suddenly be filled in with a green one.The Spinning DancerClockwise or counterclockwise? Your brain won’t be able to decide and will actually flip back and forth if you look away and back a few times. Flashed Face DistortionStare at the center of the image and the faces on either side are perceived as deformed and kind of scary. Motion-induced Blindness Look at the dot in the middle as the square rotates around it. After a moment, the yellow dots will vanish.Gathering For Gardner DragonYour brain is pretty sure this paper dragon is a convex face following the viewer around, but no. It’s a concave face taking advantage of the brain’s wishful thinking. Illusory SquareWatch as the smaller dots move through the larger ones. You could swear for a split second that there are lines connecting them in a square, but there is no square.Floating CubeThe package appears to be floating in mid air, but it’s just a concave box in front of the backdrop.Inverted ColorWatch the center of the image, and wait for it to change. It looked like a color image for a moment, right?Penrose TriangleLooking at any two corners of the Penrose triangle makes sense, but then that third one doesn’t look right. That’s why it’s called an impossible shape. The Growing CigaretteWhen the small cigarette on the left rolls to the right, it appears to get larger. Actually, they were the same size to start with.Stare at the center and the gap in the pink dots will suddenly be filled in with a green one.