#15 Rotating Snakes
This image is called "Rotating Snakes". Stare at this for a few seconds. Do the circles appear to move? This is a motion illusion- the circles look like they're moving, but they're stationary the whole time.
Motion illusions work by using common geometric shapes that your brain recognizes. Here, the shapes are concentric circles. Because your brain associates the shapes with moving, staring at the concentric circles will make it appear as if they are in motion. If you blink, you'll notice they appear to move faster. If you stare at a fixed point on the image, the circles stop moving.
Motion illusions work by using common geometric shapes that your brain recognizes. Here, the shapes are concentric circles. Because your brain associates the shapes with moving, staring at the concentric circles will make it appear as if they are in motion. If you blink, you'll notice they appear to move faster. If you stare at a fixed point on the image, the circles stop moving.
#14 Blivet
A blivet is a paradox. When you look at it from the top, you see two descending rectangular rods. When you look at it from the bottom, you see three ascending circular rods.
A blivet is an impossible object. This means your brain interprets the 2-D object as being 3-D and creates an optical illusion for you. The object is actually made of two rectangular rods. The third cylindrical rod you see is merely the space between the two rectangular rods.
A blivet is an impossible object. This means your brain interprets the 2-D object as being 3-D and creates an optical illusion for you. The object is actually made of two rectangular rods. The third cylindrical rod you see is merely the space between the two rectangular rods.
#13 Hering Illusion
You see here a central point from which blue lines radiate outwards on two sides. Two red lines are drawn vertically. While the red lines seem to bulge outwards, they are actually straight vertical lines.
The Hering illusion is one of depth perception. The red lines look as if they bulge out in the center. The brain sees the radiating lines originating from the blue point in the center. The blue point is furthest away from the edges, so the brain assumes the center of the line must also be further away in the center. This creates the optical illusion of bulging out in the center.
The Hering illusion is one of depth perception. The red lines look as if they bulge out in the center. The brain sees the radiating lines originating from the blue point in the center. The blue point is furthest away from the edges, so the brain assumes the center of the line must also be further away in the center. This creates the optical illusion of bulging out in the center.
#12 White's Illusion
In White's illusion, there are horizontal black stripes against a white background. On the left side, there is a lighter gray vertical stripe. On the right side, there is a darker gray vertical stripe. These two vertical stripes are actually the exact same shade of gray.
White's illusion tricks the brain into thinking there the lighter gray is brighter and more luminous. This optical illusion is explained by lateral inhibition, where brightness is perceived differently. On the left side, dark photoreceptors detect more light and deactivate, making the gray stripe appear lighter. On the right side, both light and dark photoreceptors are activated. Your brain struggles to make sense of what it sees, and so it perceives the gray stripe as being darker.
White's illusion tricks the brain into thinking there the lighter gray is brighter and more luminous. This optical illusion is explained by lateral inhibition, where brightness is perceived differently. On the left side, dark photoreceptors detect more light and deactivate, making the gray stripe appear lighter. On the right side, both light and dark photoreceptors are activated. Your brain struggles to make sense of what it sees, and so it perceives the gray stripe as being darker.
#11 Zollner Illusion
In the Zollner illusion, there are two sets of lines. Crosses on different lines create angling. Actually, these lines are parallel to each other.
There are a few explanations for this illusion. It uses depth perception to work. The shorter lines are angled so they look as if they are closer to us, the audience, and therefore not parallel to the longer lines. The different angles on the two lines fool the brain into thinking the lines are distorted.
There are a few explanations for this illusion. It uses depth perception to work. The shorter lines are angled so they look as if they are closer to us, the audience, and therefore not parallel to the longer lines. The different angles on the two lines fool the brain into thinking the lines are distorted.
#10 Adelson's Checker Shadow Illusion
We have here a checkerboard with dark and light colors. A green cylinder stands on top of the checkerboard and creates a shadow running diagonally across the board. Sounds simple enough. But did you notice that the squares on the checkerboard marked A and B are actually the same shade of gray?
This illusion was created by a Professor Adelson at MIT. The darker colored square A is surrounded by lighter colors which makes it appear lighter. This is called local contrast. The green cylinder casts a shadow across the board making square B that the shadow falls on look very different. Don't believe it? Check the gray values for the colors yourself.
This illusion was created by a Professor Adelson at MIT. The darker colored square A is surrounded by lighter colors which makes it appear lighter. This is called local contrast. The green cylinder casts a shadow across the board making square B that the shadow falls on look very different. Don't believe it? Check the gray values for the colors yourself.
#9 Orbison Illusion
In an Orbison illusion, there is an overlapping figure placed on top of a background of either concentric circles or radial lines. Here, there is a quadrilateral that looks distorted and bulging. It's actually a square.
This is actually a square placed on top of the radial lines. The illusion uses the perception of the background. Because the square is placed on top of the background lines, the lines of the square intersect the background and make the square look distorted. Your brain processes the angles differently and distorts the shape.
This is actually a square placed on top of the radial lines. The illusion uses the perception of the background. Because the square is placed on top of the background lines, the lines of the square intersect the background and make the square look distorted. Your brain processes the angles differently and distorts the shape.
#8 Lilac Chaser
Here, there are 12 purple dots arranged around a central black. The background is gray. Stare at the black cross for at least 30 seconds. Do the purple dots appear to disappear? Did a green disc appear? Now where'd the purple dots go?
The lilac chaser illusion is a visual illusion. The lilac dots appear to move because of apparent movement. Because the dots are spaced evenly and you're staring at the black cross in the middle, your brain perceives movement. The green disc appears by negative afterimage, where an afterimage of color appears because you're staring at the same point of color for so long. Staring at the same point also causes Troxler fading, where a blurry object on the periphery fades.
The lilac chaser illusion is a visual illusion. The lilac dots appear to move because of apparent movement. Because the dots are spaced evenly and you're staring at the black cross in the middle, your brain perceives movement. The green disc appears by negative afterimage, where an afterimage of color appears because you're staring at the same point of color for so long. Staring at the same point also causes Troxler fading, where a blurry object on the periphery fades.
#7 Kanizsa Triangle
The Kanizsa triangle makes it appear as though there is a white equilateral triangle drawn on top of a second equilateral triangle. Three black circles in a pacman-shape outside of the triangle form the points of the bright triangle.
The Kanizsa triangle was created by Gaetano Kanizsa. This type of optical illusion uses subjective contours, which create the illusion of sharp edges. The white triangle also appears brighter than the background. The darker pacman-shaped circles show a color contrast that makes the triangle appears more luminescent. Illusory contours by the circles create the illusion of the edges of the triangle.
The Kanizsa triangle was created by Gaetano Kanizsa. This type of optical illusion uses subjective contours, which create the illusion of sharp edges. The white triangle also appears brighter than the background. The darker pacman-shaped circles show a color contrast that makes the triangle appears more luminescent. Illusory contours by the circles create the illusion of the edges of the triangle.
#6 Frasier Spiral Illusion
You might be wondering why this is included. The black cords against a checkerboard background obviously form a spiral, right? Well, you'd be wrong. This is actually not a spiral.
The Frasier Spiral illusion is also known as the twisted cord illusion. This optical illusion works by playing on retinal perception. It appears as if the black cords are spiraling, but these are actually concentric circles. The black circles are combined with white twists to create a false spiral. The illusion is furthered by the misalignment in the background, where there is a checkerboard pattern.
The Frasier Spiral illusion is also known as the twisted cord illusion. This optical illusion works by playing on retinal perception. It appears as if the black cords are spiraling, but these are actually concentric circles. The black circles are combined with white twists to create a false spiral. The illusion is furthered by the misalignment in the background, where there is a checkerboard pattern.
#5 Ebbinghaus Illusion
Here, you see two groups of circles. One shows larger blue circles surrounding a small orange circle. The other one shows a large orange circle surrounded by small blue circles. Ready to have your mind blown? The orange circles are actually the same size.
This is known as the Ebbinghaus illusion. This optical illusion works by using relative size perception. Your brain interprets the orange circle on the left as small because it's surrounded by larger circles. The orange circle on the right looks bigger because it's surrounded by small circles. Your brain tricks you into thinking the orange circles are of different sizes. Try measuring them if you're still skeptical.
This is known as the Ebbinghaus illusion. This optical illusion works by using relative size perception. Your brain interprets the orange circle on the left as small because it's surrounded by larger circles. The orange circle on the right looks bigger because it's surrounded by small circles. Your brain tricks you into thinking the orange circles are of different sizes. Try measuring them if you're still skeptical.
#4 Bezold Effect
This picture represents the Bezold Effect. One side shows a lighter red that's striped with white while the other side is a darker red striped with black. Guess what? Both of these are the same shade of red.
Why do these two shades of red look so different? This is called the Bezold Effect. Wilhelm von Bezold discovered that color is interpreted by the brain differently when it is associated with different colors. Because the red on the left side is alternated with white, your brain sees it as a lighter shade of red. The black stripes on the right side make that red look darker.
Why do these two shades of red look so different? This is called the Bezold Effect. Wilhelm von Bezold discovered that color is interpreted by the brain differently when it is associated with different colors. Because the red on the left side is alternated with white, your brain sees it as a lighter shade of red. The black stripes on the right side make that red look darker.
#3 Cafe Wall Illusion
This is another classical illusion you've probably seen before. There are lines of alternating black and white "bricks" separated by a line of gray "mortar". Looks crooked, right? Wrong. These are actually parallel straight, horizontal lines.
This was first observed by Dr. Richard Gregory when he was looking at tiles on a cafe wall. The parallel lines look bent because of the position of the squares. For it to work, the black squares cannot be completely lined up. When the squares are laid irregularly, it gives the appearance of sloping lines.
This was first observed by Dr. Richard Gregory when he was looking at tiles on a cafe wall. The parallel lines look bent because of the position of the squares. For it to work, the black squares cannot be completely lined up. When the squares are laid irregularly, it gives the appearance of sloping lines.
#2 Hermann Grid Illusion
This grid illusion is known as the Hermann Grid Illusion. There are black squares arranged in a grid against a white background. Look at the intersection between the squares. Do you see a gray dot?
You see gray blobs at the intersections of the black squares when it is actually a white background. This is because of a phenomenon in the retina of the eye called lateral inhibition. The ganglion cells use photoreceptors to process what it is seeing. The area at the intersection, called the receptive field, is small. Because the intensity of black color around the intersection is high, the intersection itself appears darker- a gray color.
You see gray blobs at the intersections of the black squares when it is actually a white background. This is because of a phenomenon in the retina of the eye called lateral inhibition. The ganglion cells use photoreceptors to process what it is seeing. The area at the intersection, called the receptive field, is small. Because the intensity of black color around the intersection is high, the intersection itself appears darker- a gray color.
#1 Mobius Strip
A Mobius Strip is one of the simplest optical illusions. It's also one of the most mystifying. What results is a simple strip that only has one edge and one surface. There is no discernible "front" or "back" side. So how is this created from a strip of paper that had two sides?
To make a Mobius strip, you take a strip of paper, add a half-twist then tape the ends together. This has the mathematical property of being non-orientable and has non- Euclidean geometry. Although this seems to have multiple surfaces when you look at it, all you have to do is take a pencil and trace a line across the strip. You'll see that not once does the line go on a different "side" of the strip.
To make a Mobius strip, you take a strip of paper, add a half-twist then tape the ends together. This has the mathematical property of being non-orientable and has non- Euclidean geometry. Although this seems to have multiple surfaces when you look at it, all you have to do is take a pencil and trace a line across the strip. You'll see that not once does the line go on a different "side" of the strip.
No comments:
Post a Comment