https://optical.toys/Recent content on Optical ToysHugo -- gohugo.ioen-ushttps://optical.toys/thatcher-effect/Sun, 17 Mar 2024 00:00:00 +0000https://optical.toys/thatcher-effect/What: The thatcher effect, as you may have just experienced in the interactive examples above, shows that when a face is upside down, but its features (eyes and mouth in this case) are themselves upside down, thus appearing right side up, the brain has a hard time recognizing the face to be tampered with, or wrong at all. This is a great example of how the brain processes faces, and how it can be fooled by simple tricks.https://optical.toys/disappearing-bicyclist/Thu, 25 May 2023 00:00:00 +0000https://optical.toys/disappearing-bicyclist/What: This is one of famous puzzle makers Sam Loyd’s vanishing puzzles, Sam Loyd [1] himself is one of the most historied and famous puzzle makers and has published hundreds of thousands of puzzles. This one, the Disappearing Bicyclist is one of my favorites, using a simple rotation to hide the secrets of the puzzle, yet show you in full plain sight how it is operating. How To: This one is relatively simple to operate, count the bicyclists on the screen, and then click anywhere and count again, you’ll see that they go from 13 to 12, and hence the conundrum will arrive… where did the extra come from (or go!https://optical.toys/shepard-tone/Fri, 21 Feb 2025 00:00:00 +0000https://optical.toys/shepard-tone/What: Okay you got me! Yes, this is not an optical toy, but an auditory one… the Shepard tone was named by/after scientist (and optical illusion lover) Roger Shepard in 1964, in this paper [1], Circularity in Judgments of Relative Pitch. Honestly worth checking out, as the paper instantly references the Penrose stairs [2], as a source of inspiration. So what are we experiencing here? Well essentially a tone, or sound that feels like it is perpetually rising, or falling depending on the setting you have.https://optical.toys/watercolor-illusion/Sun, 22 Feb 2026 00:00:00 +0000https://optical.toys/watercolor-illusion/What: The Watercolor Illusion is one of those gorgeous ones where your brain is just… painting things that aren’t there. The thing about this thats beautiful, is that it’s easily paintable (water colors obviously) with your own watercolors, on physical paper. You should effectively be able to look at this illusion and figure it out (it seems to work for me in greys/blacks/whites so its color blind-independent?) … the lines drawing the shapes have a subtle shading to them in one direction, not too dissimilar to water color painting.https://optical.toys/waterfall-effect/Fri, 09 Jun 2023 00:00:00 +0000https://optical.toys/waterfall-effect/What: This is the second optical toy on this site demonstrating this effect, although the other is using spirals they have a similar effect, albeit a little more spinny. A motion aftereffect occurs when you observe a moving pattern for a while, and then begin to look at something else. How To: Stare at the center for a while, and then look at something nearby, be it the wall, art, or your own hands… you should see them appear to bulge and grow, or shrink and contract.https://optical.toys/spinning-duck/Mon, 17 Apr 2023 00:00:00 +0000https://optical.toys/spinning-duck/What: This silhouette illusion is probably one of the harder to replicate, that being said, the effect and awe of getting it working is also probably one of the most amazing to me. Here you see a duck that is spinning, the thing is, with a silhouetted image there isn’t really enough visual data to tell if it’s going clockwise or anticlockwise as there are multiple positions where the image looks exactly the same.https://optical.toys/lilac-chaser/Sat, 15 Apr 2023 00:00:00 +0000https://optical.toys/lilac-chaser/What: The Lilac Chaser is perhaps my favorite illusion of all time, largely because it combines so many different illusions into one amazing piece. It was first built by Jeremy Hinton in 2005, and has made the internet rounds many times! To get this thing going all you really need to do is focus on the dot in the center, the rest should hit you one effect after another. The first effect I observe is the afterimage effect, whereby the empty hole in the circle suddenly gives you a circle of the inverted color, so at its initial settings, there will be a green circle… that alone is amazing.https://optical.toys/zollner-illusion/Wed, 21 Jan 2026 00:00:00 +0000https://optical.toys/zollner-illusion/What: The Zöllner Illusion (pronounced TSOLL-ner, or just “zollner” if you’re not feeling fancy) is one of those delightfully old illusions that still gets me every time. It was discovered way back in 1860 by Johann Zöllner, a German astrophysicist who was probably just trying to look at fabric patterns and got thoroughly distracted [1]. Once you start playing around with the controls, the effect will be pretty clear… and it’s at least a little bit more fun to me knowing that the diagonal lines are causing my brain to glitch out.https://optical.toys/concentric-spirals/Thu, 03 Oct 2024 00:00:00 +0000https://optical.toys/concentric-spirals/What: This optical illusion is an alternate example of the “Fraser spiral” or “concentric spiral” illusion. Named by British psychologist James Fraser in 1908 [1], and while it doesn’t have rounded “loops”, the visual noise creates similar lines, causing the same effect. If you couldn’t tell already by the general vibes, this is an Akiyoshi Kitaoka recreation [2], although I’ve added the spin to enhance the effect, as well as the colors.https://optical.toys/schroders-stairs/Sat, 04 May 2024 00:00:00 +0000https://optical.toys/schroders-stairs/What: This finnicky optical illusion is called schroders stairs, which is aptly named after it’s author, Heinrich Schröder, who published the illusion in 1858 [1] The illusion uitilizes a phenomena Multistable perception, which is a type of perceptual ambiguity that occurs when an image can be seen in multiple ways. In this case, the stairs can be seen as either going up or down, depending on which side you focus on.https://optical.toys/reverse-phi-effect/Mon, 19 Jun 2023 00:00:00 +0000https://optical.toys/reverse-phi-effect/What: This illusion is an example of the reverse phi phenomenon, fooling your brain into seeing motion when there is very little, that is, colors are changing but the primary object is not. This example I’ve built is inspired by the Twitter user, @Jagarikin [1] who has posted multiple videos of similar effects including spirals and other shapes, that I also hope to re-create. However, I wanted an interactive version.https://optical.toys/titchener-circles/Mon, 19 Jan 2026 00:00:00 +0000https://optical.toys/titchener-circles/What: The Titchener Circles illusion (also called the Ebbinghaus Illusion) is one of those classic brain betrayals that really gets you. Hermann Ebbinghaus discovered this back in 1898, although it got its more popular name from Edward Titchener who put it in his textbook in 1901 and everyone just… ran with that. Even after 125+ years, researchers note that “the origin of this well-known phenomenon… is still puzzling” [1]. The effect is beautifully simple: those two orange circles in the center are exactly the same size, but your brain is absolutely convinced they’re different.https://optical.toys/ponzo-illusion/Wed, 21 Jan 2026 00:00:00 +0000https://optical.toys/ponzo-illusion/What: The Ponzo Illusion is a gorgeous example of your brain being too clever for its own good. It was cooked up by Mario Ponzo back in 1911 [1], and it’s all about how your visual system uses depth cues to judge size, even when it really shouldn’t. Those two orange horizontal lines? Exactly the same length. Your brain is doing the thing that makes the top one seem bigger. It’s seeing those converging railroad tracks and going “ah yes, perspective!https://optical.toys/stepping-feet/Mon, 30 Sep 2024 00:00:00 +0000https://optical.toys/stepping-feet/What: This interactive version of the “stepping feet” optical illusion, where both the yellow and blue walkers appear to be stepping across the screen but are in fact moving in a straight line at the same speed. The effect relies on your brain’s perception of contrast, and the way it exaggerates motion (surprise! It exaggerates motion) How To: This illusion is initially set up in the traditional way, with yellow and blue, which allows you to see that the “walkers” are moving uniformly if you look at them individually, but also see the effect of the illusion when you don’t concentrate particularly hard on just one.https://optical.toys/rgb-color-assimilation-ball/Sat, 20 Jul 2024 00:00:00 +0000https://optical.toys/rgb-color-assimilation-ball/What: The official name for this optical illusion, is Color Assimilation[1] or the Bezold Effect[2], which would be the most concise way of describing what is happening here. If the illusion is working correctly, as it does on me, you will see a grey ball, with a multi-striped background with one layer of overlaying lines, to your eyes, the grey ball will assume the color of its overlaying stripes. As you change which color lines specifically overlay, the ball will follow suit again, even though it remains grey the entire time.https://optical.toys/contrast-effect/Wed, 17 Apr 2024 00:00:00 +0000https://optical.toys/contrast-effect/What: This optical illusion is a little tricky to categorize, but I’ll put it in the category of “contrast effect” [1], although in this example we’ve got an animated circle shifting from left to right, as opposed to two fixed objects. The effect was noted by Ibn al-Haytham[2] who famously wrote a book on optics over 1000 years ago, this effect in particular was noted in regards to drying paint!https://optical.toys/checkerboard-angles/Wed, 28 Feb 2024 00:00:00 +0000https://optical.toys/checkerboard-angles/What: This illusion should hit fairly clearly, there is a checker board pattern, with a small diagonal set of checkers within each corner with an alternating pattern. This pattern though, switching the black and white squares starts to twist your mind, and suddenly it seems like the lines, especially around the edges are on angles rather than perfectly vertical. This particular effect, I first ran into in a blog called Revolution Analytics[1], whereby the owner was creating effects using the programming language R.https://optical.toys/persistance-of-vision-static-cube/Sat, 24 Feb 2024 00:00:00 +0000https://optical.toys/persistance-of-vision-static-cube/What: This optical effect is relatively simple to experience, as the cube flies through the space, it’s edges are changing any pixel behind them from black to white, and vice versa. When the cube stops moving, the effect is lost, and the cube is no longer visible. I first ran into this demo on a video by Chris Long[1], where he throughfully explains how he’d stumbled into the effect in the 80’s, and a nice step by step on building out the effect from simple lines to beyond.https://optical.toys/shifty-peaches/Sun, 21 May 2023 00:00:00 +0000https://optical.toys/shifty-peaches/What: This isn’t the first time we’ve got some Akiyosi Kitaoka [1] on the site, and it won’t be the last. This is a classic example of illusory motion, where the balls appear to be moving in the peripherals of your vision, but are in fact completely still. How To: Mix up the colors, sizes, and spacing to see how it affects the illusion. I found that the illusion is strongest when the colors are contrasting, and the balls not super large, although I could see it therehttps://optical.toys/motion-aftereffect/Thu, 20 Apr 2023 00:00:00 +0000https://optical.toys/motion-aftereffect/What: This optical illusion (though im not entirely sure it falls into the illusion category) demonstrates an effect that occurs when you observe a moving pattern for a certain amount of time, and then begin looking at something else. This can occur naturally in nature, such as looking at a waterfall and then observing the cliffs beside it. I have also coded up another version of this similar effect A similar effect on this site!https://optical.toys/bamboozled/Tue, 18 Apr 2023 00:00:00 +0000https://optical.toys/bamboozled/What: Bamboozled is one of my favorites, mostly because I stumbled upon it from this meme [1] and decided It must be a part of the Optical Toys collection. The perception here is that the tall bamboo sticks appear to be both angled and will move back and forth in the peripherals of your vision. How To: You can change the sizes and amount to make the illusion stronger for you, as well as mess with the colors.https://optical.toys/dots-that-will-quit/Sun, 16 Apr 2023 00:00:00 +0000https://optical.toys/dots-that-will-quit/What: Some dots are here to stay, and others disappear, or at least that’s how it goes in this illusion, fantastically named an Extinction Illusion, named by its creator Jacques Ninio [1] … In this optical toy when you focus a single dot you’ll see (or not see?) that the other darker dots vanish, while it goes against my intuition, it’s named here as a variant of the Hermann Gridhttps://optical.toys/dots-that-wont-quit/Sun, 16 Apr 2023 00:00:00 +0000https://optical.toys/dots-that-wont-quit/What: While I still feel that “dot’s that won’t quit” is a better name, this illusion is actually called the scintillating grid illusion which was discovered by Elke Lingelbach in 1994, although it also falls into the category of Hermann Grid Illusion [1] (I don’t have this one built yet, but will in future!) The effect is simple and strong, you’ll see dark dots appearing in the intersection circles when they aren’t there!https://optical.toys/healing-grid/Sun, 16 Apr 2023 00:00:00 +0000https://optical.toys/healing-grid/What: The Healing Grid illusion is an optical illusion by Scientist Ryota Kanai, and was a finalist in the 2005 illusion of the year competition, with this peripheral trickery. How To: To get this illusion happening you’ll need to stare into the center, being careful not to look too far to your peripheral vision, eventually there will be a subtle healing of the grid. The effect isn’t staggeringly strong and can take a little while.https://optical.toys/illusory-motion-beans/Sun, 16 Apr 2023 00:00:00 +0000https://optical.toys/illusory-motion-beans/What: This effect, and honestly the largest body of work you’ll see when you look into both optical illusions and illusory motion has been created by Japanese artist Akiyoshi Kitaoka, a true master of the art. If the illusion didn’t immediately hit you, there is no animation at all happening within the illusion, it’s 100% your brain playing tricks providing a weird spinning motion in the peripherals of your vision.https://optical.toys/cafe-wall/Sat, 15 Apr 2023 00:00:00 +0000https://optical.toys/cafe-wall/What: This one should hit you fairly quickly, but if it hasn’t yet, it’s that the lines are all horizontal here, but appear to your brain to have angles… the illusion has a couple of names, it was first named the Kindergarten pattern in 1898 [1] After a weaving pattern, and later as the Cafe Wall Illusion brought back into the light by Richard Gregory [2], which it is most commonly named now.https://optical.toys/gradient-motion/Sat, 15 Apr 2023 00:00:00 +0000https://optical.toys/gradient-motion/What: This illusion, created by Alan Stubbs in 2006 [1], has the neat effect of a growing light (or shadow if you customize above to those colors) when you move your head towards and away from the image. It has the extra effect of making you look like you’ve forgot your glasses and are trying to read whats on screen, or like you’re straight up a chicken. How To: Sit straight on from the screen and move your head back and forth, like a bird.https://optical.toys/kaleidoscope/Sat, 15 Apr 2023 00:00:00 +0000https://optical.toys/kaleidoscope/What: Ok, this one is clearly not an optical illusion, but it’s a great optical effect that translates really well into the digital era, that said, if you get your hands on a physical one the tactile response is very fun! It’s inclusion is important because the kaleidoscope is one of the very first optical toys, the name coined by it’s inventor David Brewster, in 1815 [1] … he was later knighted for his work, in 1831, so thats Sir David Brewster.https://optical.toys/ouchi-illusion/Sat, 15 Apr 2023 00:00:00 +0000https://optical.toys/ouchi-illusion/What: The Ouchi illusion is an illusion named after its inventor, Japanese graphics artist Hajime Ouchi [1], in 1977, you’ll notice that the disc in the center appears to hover above the background, and when you’re moving your head it can appear to be moving slightly when in reality we know its static and a fixed 2D circle. How To: You’ll be able to ramp up the intensity of this one by increasing the contrasting colors (black and white being the original artist’s design), also the length and height of the rectangles can be changed, for me when they are short and long (or long and short) the illusion is strongest.https://optical.toys/troxler-fade/Sat, 15 Apr 2023 00:00:00 +0000https://optical.toys/troxler-fade/What: The Troxler fade, named after the discoverer Ignaz Paul Vital Troxler [1], was documented in 1804 in his paper named “On the disappearance of given objects from our visual field” (that’s an English translation, it was in German). You’ll notice, as you stare into the center and focus on it, the outer ring begins to fade, and then eventually disappears entirely… it will take moving your head or a hard blink to see it again.https://optical.toys/no-spirals-spirals/Fri, 14 Apr 2023 00:00:00 +0000https://optical.toys/no-spirals-spirals/What: The real name for this illusion is the intertwining illusion, which was documented by Dr. Baingio Pinna in 2002 [1], is the first of Pinna’s illusions that I’ve re-coded up in optical toys, and is my personal favorite. If you hadn’t picked up on it already the illusion is a series of concentric circles, yes concentric, and is not at all a spiral. How To: There are some neat things to play with here, primarily you can change the angles to see when the illusion is strongest for you and when it breaks completely… The same goes for the colors of the squares and background, you’ll notice that the contrasts are key to making it stronger!