Convex / Concave, it all depends on your point of view!
Although the plates are the same, in the second picture, the indents of the egg plate look more like convex domes rather than concave indents.
Convex / Concave
Paradox
Perpetual Motion
Is this a real perpetual motion machine?
Obviously not… The closest thing to a “perpetual motion machine” is the Beverly clock whose mechanism is driven by variations in atmospheric pressure, and by daily temperature variations.
Ghost Colors
This is one of my earliest color optical illusions. There is no yellow or green in the diamond shapes, just vertical black lines! (If you don’t believe it, use a eyedropper tool to check it.) This intriguing visual effect is mainly due to “simultaneous color contrast induction“.
Color Luminance Sensibility
Do the light gray triangular shapes in the diagram below have the same hue and brightness?
Magic Tic-Tac-Toe
Our visual system can interpret colors and shades in surprising ways. This 3×3 Tic-Tac-Toe grid, for example, showcases how easily our perception of brightness can be fooled.
Do you notice anything unusual in the grid below?
The looping animation below brings the illusion to life, revealing the trick in action. That large green square behind the grid isn’t actually uniform—it’s made up of alternating dark and light green squares. Our visual system works like a “comparative computer”. In fact, we never see colors in isolation, as the appearance of any color is affected by the colors surrounding it. So, under certain conditions, colors that are identical may appear different, while colors that are different may look the same. In our visual system there is a mechanism that enhances the contrast of the outline of an object relative to its background: it is called “lateral inhibition”.
Show / Hide the Trick
Thus, even small differences in brightness between adjacent zones, or objects, are deliberately increased by our visual system and the brain to better distinguish them. But something strange happens when the brightness boundaries of the color zones are concealed: the cues the brain needs to trigger the lateral inhibition no longer exist and consequently we become blind to variations in color brightness, as shown in the animated gif.
Recognitions
My optical illusion “Magic Tic-Tac-Toe” has been chosen to be among the top 10 finalists for the “2019 Best Illusion of the Year Contest”
PERCEPTION OF BRIGHTNESS
In the example below, in the left column, you can see two apples—one green, one red—appearing as a single solid color with a black cross over them. Now, if we remove the thick black lines, each apple clearly appears divided into four quarters of different shades—even though they are exactly the same in both columns, with and without the black cross.
Here’s a trickier version: with the black grid in place, the large green square appears uniform. Take the grid away, and it turns into a full-on checkerboard…
This occurs because in our visual system there is a mechanism that enhances the contrast of the outline of an object relative to its background: it is called ‘lateral inhibition’. Thus, even small differences in brightness between adjacent zones or objects are deliberately increased by the brain to better distinguish them. So, when the brightness boundaries of the color zones are concealed, the cues the brain needs to trigger the lateral inhibition mechanism no longer exist and consequently we become “blind” to variations in color brightness. The illustrations above have been taken from my book “Drawing Optical Illusions” who was translated in many languages. The book is still available from Amazon.
This eye-catching, colorful book is designed to inspire those artists interested in optical illusions and as an invaluable reference tool for people who to wish to create them. In clear, easy steps, this book shows people how to design a range of original and classic optical illusions and even how to create their own personalized illusions.
Optical Illusions, An Eye-Popping Extravaganza of Visual Tricks
“Reality is merely an illusion,
albeit a very persistent one.”
— Albert Einstein
Everything you “see” depends strongly on the context and attention you give to it. The mind and the world you experience are inseparable, as it is your 3-pound brain that make the world meaningful. Seeing isn’t some kind of direct perception of reality. Actually, our bairns are cnostanlty itnerperting, correcting, and giving srtuctrue to the viusal ipnut form our eeys. If this were not the case, you would not see any colors (consider that all the beautiful colors you see don’t really exist), and you would probably see the world upside-down! Moreover, you would notice in your visual field a very large dot, called the “blind spot,” where the optical nerve enters the eye.
A Zen master said once: “If you pour water into a cup, water becomes the cup; if you fill a bottle with water, it becomes the bottle!” Likewise, the context shapes the appearance of the world surrounding you. Your brains work by comparing information and stimuli: contrasting colors, shapes, depth in a dynamic changing environment … that’s why perception is relative and not absolute. Continue Reading
Dynamic Müller-Lyer Illusion
I am very proud that my “Dynamic Müller-Lyer Illusion” won the third prize as best illusion of the year 2017!
As you surely know, the “BEST ILLUSION OF THE YEAR CONTEST” is a yearly competition under the patronage of Scientific American, organized by the Neural Correlate Company (New York, USA).
Müller-Lyer’s illusion proves that a segment can visually appear longer or shorter depending on the sense of the arrow heads at its ends. In what consists my variant? As shown in the animation, the red dot in the middle of the line is equidistant from the other two red dots, although the ends of the line visually appear to alternately stretch and shrink like a rubber band!
The radial version of the illusion is even more impressive:
The perceptual increasing and decreasing of the segments occurs in a very short time. Thus, I suppose it is more a physiological phenomenon, rather than a psychological bias. Our attention seems to be attracted by the receptive field WITHIN the V-shaped arrow heads, causing an illusory inward or outward shift of the ends of the line.
The Bullephant, an earliest bistable figure
Visual illusions where you experience two equally possible interchangeable states in perception are called “bistable illusions“. The Necker cube and the Rubin vase are ones of the most classic examples of a bistable figure. I have discovered that all over India, you may see many variants of an interesting bistable depiction, which represents a bull and an elephant with distinct bodies and only one head (painted or sculpted at least 850 years ago). If you look carefully at the whole picture, you may see how the body parts of both animals are skillfully overlapped. For instance, the trunk of the elephant is also the hump of the bull. The horns and ears of the bull have become the mouth or snout of the elephant. These are ones of the earliest documented “ambiguous figure” illusions…
TangraMagic Puzzle
TangraMagic, a new manipulative puzzle for classrooms or just for fun..
This unique puzzle of my creation is ideal for teaching math basic skills, problem solving and critical thinking in an exciting way! The vanishing geometrical effects will hold juniors and seniors’ attention. All the secret of this game is concealed in two numbers: 5 and square root of 7.
