Zebra Puzzles
A row of houses, a handful of lists, and a page of clues that fit together exactly one way. Tap a name to place it, or rule it out. Every clue is needed, nothing needs guessing, and the hint tells you which clue forced what.
Also called a logic grid puzzle or an Einstein puzzle.
Related Practice
What Is A Zebra Puzzle?
A zebra puzzle gives you a row of positions — houses along a street, desks along a wall, carriages on a train — and several lists of attributes. Each list has exactly one entry per position: one person, one colour, one pet, one drink. A page of clues describes how they sit together, and exactly one arrangement satisfies all of them at once. The puzzle is named for its most famous version, which ends by asking who owns the zebra.
Zebra Puzzle, Logic Grid, Einstein Puzzle
All three names describe the same thing. Logic grid refers to the paper aid most solvers use: a lattice of every attribute against every other, ticked and crossed as facts arrive. Zebra puzzle names the classic instance. Einstein puzzle is the one to be careful with — the puzzle is very often introduced with a claim that Einstein wrote it and that only two per cent of people can solve it, and neither half has ever had a source attached to it. The earliest known printed version ran in Life International in 1962, unsigned.
The Clues, And What Each One Really Tells You
There are seven kinds of clue here, and knowing what each one eliminates is most of the skill. Notice how much more the ordering clues do than they appear to:
| Clue | Example | What it rules out at once |
|---|---|---|
| Direct | Ben lives in the third house. | Everything else in that row, and Ben everywhere else |
| Together | Alice and the dog owner are in the same house. | Every position one of them cannot occupy, for both |
| Apart | Clara and the tea drinker are not in the same house. | One position each, once either is known |
| Immediately right | The green house is immediately right of the blue. | Green from the first position, blue from the last |
| Next to | Dev is next to the cat owner. | Any position not adjacent to a possible partner — but not the side |
| Somewhere left | The milk drinker is somewhere left of Elif. | Milk from the last position, Elif from the first — and more as the range narrows |
| Gap | There is exactly one house between X and Y. | Every position without a partner at that exact distance |
Eliminating Is The Whole Method
Beginners hunt for clues that place things, and there are rarely more than one or two. The puzzle is actually solved by the opposite move: striking off what cannot be. Once a value has a single position left it belongs there, and once a position has a single value that can still take it, that is settled too. Nearly every fact in a zebra puzzle arrives as the last one standing rather than as a direct find, which is why this board gives ruling out a mode of its own rather than hiding it behind a gesture.
Every clue here is load-bearing. After a puzzle is generated, each clue is removed in turn and the puzzle re-solved; the clue only stays if the puzzle stops being deducible without it. So if you are stuck and there is a clue you have not used, it has not been used yet — it is not scenery. That is checked on every puzzle before it reaches you, not left to the setter's judgement.
Why The Ends Of The Row Matter Most
Ordering clues are worth more than they look, and the reason is the edges. Nothing can sit immediately to the right of the last position, and nothing is somewhere to the left of the first, so every ordering clue immediately removes an end from one of its two subjects. Two such clues pointing the same way stack: if A is left of B and B is left of C, then A cannot be in the last two positions at all. Working outward from the ends is usually faster than working from the middle.
Zebra Puzzles Frequently Asked Questions
What is a zebra puzzle?
A logic grid puzzle: a row of positions — houses, desks, carriages — and several lists of attributes, one of each per position. Clues describe how they relate, and exactly one arrangement fits them all. The name comes from a famous version that ends by asking who owns the zebra.
Is a zebra puzzle the same as a logic grid puzzle?
Yes — the same puzzle under two names. Logic grid describes the paper aid most solvers use; zebra puzzle names the classic example. They are also called Einstein puzzles, though there is no evidence Einstein wrote one.
Did Einstein really write the zebra puzzle?
Almost certainly not. The earliest known printed version appeared in Life International in 1962, unsigned. The Einstein attribution — and the claim that only 2% of people can solve it — appeared much later and has no source behind it.
How do you solve a zebra puzzle?
Two moves, repeated. Take the direct clues first — they place a value outright. Then eliminate: most clues rule things out rather than place them. When one value has a single place left, or a place has a single value left, that fact is settled.
What does "next to" mean in a zebra puzzle?
Immediately adjacent, on either side — the positions differ by one, but you are not told which way round. Immediately to the right of is the stronger form that does fix the order.
Why does every clue matter?
Because they are stripped back until none can go. Each clue is removed in turn and the puzzle re-solved; it is only kept if the puzzle stops working without it. So an unused clue is still needed — that is a guarantee, not a hint.
Do you ever have to guess?
No. Every puzzle is checked twice before you see it: an exhaustive count confirms exactly one arrangement fits, and a separate solver restricted to ordinary deduction must finish without ever branching.
What is the hardest kind here?
The families where no clue names a position outright. Without a free placement to start from, every position has to be reached through relationships alone, and the first certain fact can arrive a long way in.