Category: art

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GHOST COLORS (2)

Take a closer look at the image below—you’re in for a mind-bending surprise! There’s absolutely NO yellow, and not even red or green in sight. (Zoom in if you don’t believe it!) The only actual colors used are blue, cyan, and magenta.
What you’re seeing is a fascinating phenomenon known as “simultaneous color contrast” and “color assimilation”.—effects that ‘trick’ the brain into perceiving colors that aren’t really there.

© Gianni A. Sarcone

When you magnify a portion of the image in Photoshop, as seen below, to the right, you see a series of black bars. Some gaps that appeared yellow at first are actually pure WHITE, and the eyedropper tool confirms that only CYAN and MAGENTA are present.

The green tint perceived in some areas is a result of the interaction between black and cyan, just as the appearance of red is due to the interplay of black and magenta. As for the yellow-looking circle, it’s actually an optical effect caused by the white space between the black bars reacting to the surrounding dark blue lines — a classic case of simultaneous contrast.

© GIanni A. Sarcone

⇨ Learn more.

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Assembly Fail: The Impossible Ikea Chair

Sometimes, following the instructions doesn’t lead to the expected result. This visual illusion explores how perception, logic, and a touch of ambiguity can turn a simple assembly into something entirely unexpected.

impossible chair
© 2002, Gianni A. Sarcone.

Now available on our Gallery shop—ideal for lovers of visual humor, design fails, and optical absurdities.

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Impossible rectangle?

Cut out the two identical, imperfect rectangles shown here—each missing two corners. Follow the lines to divide them into four geometric pieces… Then try to reassemble them into one perfect rectangle.

Sounds simple? Think again! Solve it? Tell us what made it such a brain-bender!

I’ve always had a passion for puzzles made of simple geometric pieces—especially those that seem almost impossible to solve despite the deceptively simple shapes and limited number of elements. As an Op Art artist, I find these visual enigmas a delight not only for the eye but also for the mind. For someone drawn to minimalism like me, beauty lies not just in pure form, rules, or apparent simplicity, but in the very intention of the game: to create something concrete and well-defined out of very little. And yet, at first glance, the pieces rarely seem to match the information at hand—as if something’s always missing, or as if the pieces resist aligning with your will.

Back in the ’80s, I created numerous puzzles with these paradoxical traits—some even became worldwide hits. When people would say, “Ah, so you’re the creator of that devilish puzzle?” I would always reply, “No, not a puzzle, but a piece of optical art.” Or: “No, not a puzzle, but a visual paradox.” Or sometimes: “No, not a puzzle, but a moment of zen-like reflection.”

No, I’ve never created puzzles—but rather works that turn geometry into visual meditation.

⇨ More visual enigmas to create.

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The Trapezoid Trap

Here’s a rather tricky puzzle—perfect for the classroom or a fun activity with your kids (and possibly an excuse to sharpen your own spatial skills).

Print and cut out the five puzzle pieces (see Fig. A), then try to fit them all into the larger shape (Fig. B) without overlapping. Yes, it’s possible… As you may have noticed, all the pieces—including the final shape—are similar right trapezoids. They do, however, vary in scale, just to keep things interesting.

Cut out the 5 puzzle pieces (right trapezoids; fig. A) in order to fit them all into the larger shape (fig. B) without overlapping.

You can download the full template in PDF format here.

The first person to post a correct solution will receive a set of our original postcard designs.

And if you find yourself strangely fascinated by these slanted quadrilaterals, you’re not alone. Even ancient Greek mathematicians toyed with shapes like these to explore proportions and symmetry. Curious about trapezoids (or wondering if they’re secretly out to get you)? Here’s a helpful read: https://en.wikipedia.org/wiki/Trapezoid

Happy puzzling—and remember, if it feels impossible, you’re probably getting close.

(Hint: Some pieces may need to be flipped over, as if seen through a mirror.)

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UMBRELLA ILLUSION

One of my illusions from the late ’90s. Take a look at the colorful umbrellas in Figures A and B—are they the same or different? About 80% of people will say that Umbrella A has jagged, zigzag edges, while Umbrella B has smooth, wavy lines. But here’s the trick—you’ve been fooled by the brightness contrast of the rays inside the umbrellas. In reality, both umbrellas are identical in shape, perfectly congruent.

This illusion shows a phenomenon called curvature blindness, which was rediscovered in 2017 by Japanese psychologist Kohske Takahashi. He created a powerful variant and studied its impact on how we perceive shapes.

© Kohske Takahashi – The wavy lines appear different depending on the background and how the repetitive dark color is applied to them.

⇨ Read further

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Voyage au centre de la géométrie

“Voyage au centre de la géométrie” est une rubrique emblématique que nous avons eu le plaisir de tenir pendant de nombreuses années dans la célèbre revue suisse ‘Mathécole‘. Très appréciée des enseignants et du grand public, cette rubrique visait à rendre les mathématiques accessibles et fascinantes pour tous.

Bien que Mathécole, un puissant outil de diffusion des mathématiques, ne soit plus publié, vous pouvez encore consulter ou télécharger gratuitement certains numéros contenant nos articles via les archives en ligne. Nous vous invitons à les explorer et à redécouvrir la richesse de ces contenus :

· Le puzzle outil didactique 1: #173,

· Le puzzle outil didactique 2: #177,

· Le puzzle outil didactique 3: #179,

· Découper, assembler, comprendre: #183,

· Métamorphoses géométriques: #184,

· La courbe dans tous ses états: #189,

· Parcours et détours: #196.

Ces archives témoignent de l’importance de Mathécole dans la vulgarisation des mathématiques et de son impact durable. N’hésitez pas à parcourir ces articles pour en apprendre davantage et pour vous en inspirer !

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Useful Topology

In this video, a practical application of topology is presented through a simple knot technique for styling plant pots. This method transforms standard planters into trendy hanging displays.

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The Red Wine Color Illusion

Does the color of wine change when poured into a glass?
Although it may appear darker, the red shade remains the same. This visual trick is a result of the Munker-White illusion—where our brain perceives colors differently depending on their surrounding context.

If you’re intrigued by puzzles like this, reach out to my syndication agent to feature them in your publication.

This op art piece is also available as prints and canvases in our online gallery.