A cyclic elimination
A regular elimination, repeated in a circle, ends up hiding a surprisingly clean structure. The pattern takes a while to appear, but when it does it no longer admits…
Open riddleTimeless ingenuity
Classic riddles
This collection brings together classic problems that have lost none of their power to surprise. Their solutions often look simple afterwards, but finding them requires a change of perspective.
28 riddlesAll riddles in this topic
Brothers and Sisters
The same family can look different depending on who is counting it. The trick is not to solve a large equation, but to remember that the speaker is part of the group too.
Open riddleExactly Fifteen Minutes
Two very simple mechanisms can be combined to achieve a precision that neither possesses on its own.
Open riddleRaw or Hard-Boiled?
Two eggs look exactly alike. You have only a table and your hands, yet one brief motion test is enough to reveal what each shell contains.
Open riddleSix glasses
A single action, a single idea, an exact result.
Open riddleThe Bottle and the Cap
This riddle looks so easy that it almost invites you to answer without thinking. But the important phrase is not the total price; it is the difference between the two…
Open riddleThe bridge and the lantern
Crossing a bridge at night with just one flashlight seems like a speed problem. Maybe it's not entirely.
Open riddleThe Chinese Farmer's Riddle
The Chinese Farmer's Riddle comes from the tradition of well told problems: a simple framework, a clear difficulty and a solution that seems almost obvious when it has…
Open riddleThe Clock Chimes
When a clock strikes, the important thing is not the number of chimes, but the gaps between them. That is the little trap.
Open riddleThe elephant and the boat
There are weights that no conventional scale can measure. Sometimes the solution is not to look for a bigger scale, but to think differently.
Open riddleThe Ever-Missing Euro
Some puzzles do not hide a difficult calculation, but a badly framed sum. Everyone here knows how to add, yet almost everyone adds things that should not be added.
Open riddleThe four turtles
A curved chase with four participants and a symmetry that is not broken at any time.
Open riddleThe inheritance of the 17 camels (Arab tradition)
A simple framework, a clear difficulty and an exit that seems almost obvious when it has already been seen: these are the best distribution problems of the Arab…
Open riddleThe King's Two Stones
When someone cheats, sometimes you do not need to accuse them. You only need to force the cheater to accept the consequences of their own lie.
Open riddleThe Knot Without Letting Go
Sometimes the solution is not in what you do after starting, but in how you start. If you place your body correctly before touching the rope, the knot almost appears…
Open riddleThe Lo Shu magic square
Lo Shu is one of the oldest and most elegant magic squares. With only the numbers 1 through 9, it forces rows, columns, and diagonals to obey the same sum: 15.
Open riddleThe Missing Half
Average speeds are treacherous. Sometimes they cannot be made up for—and by the time you notice, all the time is already gone.
Open riddleThe monk and the mountain
A trail, two days and a conclusion that seems impossible to guarantee until you find the right angle to look at it.
Open riddleThe Photo with No Siblings
Sometimes a family phrase looks like a maze only because we read it too quickly. This riddle hides nothing: you only have to translate each relationship without adding…
Open riddleThe Race with a Hidden Head Start
A 10% head start is not always offset by running 10% faster. The trap is to notice how much distance each runner actually has to cover.
Open riddleThe stick of a hundred ants
One hundred ants, one meter stick, and a simple rule when they meet. The result seems to depend on everything — positions, directions, collisions — but there is…
Open riddleThe three vessels of the wise man (ancient India)
The Three Vessels of the Sage belongs to the great tradition of problems that seem narrative and turn out to be exact. It preserves that ancient flavor in the…
Open riddleThe Tower of Hanoi
Few pieces unite mechanism and growth so well. Each movement is simple; The amazing thing appears when that simplicity is repeated until an unexpectedly large quantity…
Open riddleThe Truck, the Bridge, and the Bird
This riddle looks like a question about a bridge's weight limit, but it is really a question about the exact moment at which you look at the scene.
Open riddleThe two ropes
The strings are not clocks: they burn capriciously, without respecting proportions or halves. And yet, with just a lighter and some ingenuity, they can measure time…
Open riddleThe wise men and the pearls (ancient Persia)
It has the charm of old scale problems: few movements, very expensive information and a solution that must be clean from the beginning. It does not ask for brute…
Open riddleThe wolf, the goat and the cabbage
A river, a small boat and three passengers who cannot stay with just any company. The farmer will have to come and go more times than seems necessary.
Open riddleWorld Cup Stars
Three footballers, three national teams, and a survey that looks straightforward. But there is a small logical trap...
Open riddle
Support the project
No ads. No algorithm. Just craft.