We spent the whole day debating this triangular puzzle. And you, can you solve it?

 

Have you ever stumbled upon a puzzle so simple it seems to stick with you all day? This little triangle, shared thousands of times on social media, has exactly that effect. At first glance, nothing extraordinary. And yet, behind its unassuming features, it hides a mystery that has caused amused panic in many an office. The question? How many triangles are actually hidden within it? Spoiler alert: it's not as obvious as it looks…

Why is this puzzle so fascinating?

It all starts as it often does: someone shares the image, convinced they have THE right answer. Their colleagues chime in with completely different numbers… and the friendly competition begins. Some see four, others twelve, twenty-two, or even thirty-seven. And then there are those who question everything: “But if the lines aren’t perfectly straight, is it still a triangle?” In short, enough to drive even the most zen person crazy.

What makes this puzzle even more irresistible is that everyone thinks they've followed an infallible logic.  It's a bit like trying to understand why a soufflé refuses to rise , despite a recipe you think you've mastered.

Expert opinion: a clear answer… at the beginning

To settle the matter, several geometry specialists were consulted. All—or almost all—arrived at the same answer: 18 triangles. Their method? Start from the top vertex and observe how many pairs of points can form a base on each of the three horizontal lines. Three levels, six possibilities per level… voilà, 18. Easy peasy.

The explanation is elegant, logical, reassuring. You think to yourself, "Ah, finally! The mystery is solved!" Except it isn't. The story could have ended there, but the internet never sleeps…

And then… everything joyfully spirals out of control

A perceptive reader then noticed a previously overlooked detail: the drawing was done on lined paper. In other words, the background lines could also create triangles. Result: 17 additional triangles. Total: 35.

We thought we had a solid answer? Wrong.

In the following days, other enthusiasts examined the image as if it were a treasure hunt. Some spotted new possible intersections, others pointed out overlooked mini-shapes. One volunteer unearthed seven more. Still others spotted unexpected structures in the corners. The count climbed, and climbed… up to 42, then 61.

At this stage, the puzzle is no longer a simple geometric figure: it's a serial novel. Each new observation reignites the plot. We begin to scrutinize the drawing as if we were searching for  the last square of chocolate in the cupboard .

Why we love these kinds of puzzles

The reason this simple triangle has generated so much discussion is because it touches on something profoundly human: the desire to understand, to uncover a secret, to see what others don't. It's playful, pressure-free, and incredibly satisfying when you discover a new detail.

And let's face it: we all love feeling that our way of observing the world can lead to a small personal victory. A bit like finding the last piece of a puzzle or spotting the perfect deal during the sales.