Einstein's Puzzle (Five Houses Riddle)
The famous five-houses riddle, often called Einstein's puzzle or the zebra puzzle: five neighbors live in a row of houses, and a list of clues is enough to work out every detail. We generate a brand-new version every time you play.
How to play Einstein's Puzzle
- Every puzzle is a set of people, and each person matches exactly one item from every category: one pet, one drink, one house and so on. No two people share an item.
- Read the clues and mark the grid. Tap a square once for ✕ (these two do not go together) and again for ● (they do). A third tap clears it.
- With Auto-✕ on, placing a ● crosses out the rest of its row and column for you, because each item matches only one person.
- Use every grid, not just the people grids: if Ava owns the cat and the cat owner drinks tea, then Ava drinks tea.
- Order clues such as directly to the left of, younger than or next door to refer to the one ordered category in the puzzle (house numbers, ages, prices, places or weekdays).
- The puzzle is solved when every person has the right ● in each category. Every puzzle has exactly one solution, and you never need to guess.
- This page always uses the full 5 × 5 street: five neighbors in houses 1 to 5, each with a house color, a pet and a favorite drink.
Controls
- Tap or click a square to cycle ✕ → ● → empty. Right-click places a ● directly.
- On phones, switch between grids with the buttons above the grid; on wide screens all grids are shown together.
- Undo (or the Z key) steps back, Check outlines wrong marks, Hint places one correct ●. Tap a clue to cross it off.
Tips
- Start with the direct clues ("Ava is the tea drinker"), then the negative ones. Each ● gives you a full row and column of ✕ marks for free.
- Look for a row or column with only one empty square left: it must be the ●.
- "Either…or" clues are powerful: they rule out every other option for that person at once.
- For order clues, think about the ends. Someone who lives "directly to the left of" another person cannot be in the last house.
FAQ
Why is it called Einstein's puzzle?
The five-houses riddle is popularly credited to Albert Einstein, with the claim that few people can solve it, but there is no evidence he wrote it. The puzzle type is better known among puzzle fans as a zebra puzzle.
How do you solve a logic puzzle grid?
Mark an ✕ wherever a clue says two things do not match and a ● where they do. When a ● goes in, the rest of its row and column become ✕. Combine facts across grids, and keep going until every row has one ●.
What sizes and levels are there?
Choose 3 × 4 for a gentle start, 4 × 4 and 4 × 5 for everyday solving, or 5 × 5 for an expert challenge. Easy puzzles include more direct clues; Hard puzzles use the fewest clues possible, with more negatives and order clues.
Is every puzzle solvable?
Yes. Puzzles are generated by our own code and checked by a solver, which confirms that the clues lead to exactly one answer.
How is the score calculated?
Bigger grids and harder levels are worth more points, with a bonus for solving quickly. Each hint costs 40 points and each check costs 15.