Tents and Trees Puzzle Generator
Pitch one tent for every tree, directly beside its own tree, with no two tents touching — not even diagonally. The row and column totals tell you how many tents go where. The subtlety is the word *own*: it is not enough for every tent to sit next to some tree, because the tents and trees must pair up one-to-one, and a layout can satisfy every total while making that pairing impossible.
What this generator does
Places tents first, never adjacent to one another, and gives each its own tree in a neighbouring cell. Row and column totals are read off the finished layout, and the puzzle is published only when solving from those totals yields exactly one arrangement — with the tree-to-tent pairing confirmed to be a perfect matching rather than merely plausible.
How to use this tool
- Choose a grid size and generate a puzzle.
- Pitch one tent per tree, directly above, below, left or right of it.
- Keep the row and column totals exact, and never let two tents touch.
- Check that each tree can claim a tent of its own — that is the rule most people miss.
Understanding the controls
- Grid size
- Between 4 and 8. The number of trees scales with the grid, at roughly one for every six cells.
- Show the answer
- Places the tents on the grid. Hidden by default so the puzzle can be printed or shared unsolved.
- Seed
- Any word reproduces exactly the same trees, totals and solution.
Common use cases
- Printable tents-and-trees puzzles for a puzzle page or a quiet activity
- Teaching matching as a constraint, in a form that needs no graph theory to enjoy
- Practising the row-and-column counting deductions the puzzle rewards
- Test instances for a tents solver
- Setting the same puzzle for several people from one seed
How this generator works
The solver walks the grid cell by cell, either pitching a tent or skipping, pruned by the row and column totals still outstanding and by the rule that no tent may touch another. A candidate layout is accepted only if a perfect matching exists between trees and tents — computed with augmenting paths, the same method used for assignment problems — because counting adjacency is not the same as pairing everything up.
Randomness and fairness
The tents, trees and therefore the totals are random. A seed reproduces the same puzzle exactly and is therefore explicitly not cryptographically secure. Without a seed the browser's cryptographically secure generator is used.
For how randomness is produced across the whole site, see how Generate Random works.
Limitations and good to know
- Square grids from 4x4 to 8x8.
- The tree count is derived from the grid size rather than chosen directly.
- Difficulty is not graded, and a sparse grid is not always the easier one.
- Occasionally no uniquely solvable layout turns up and the tool asks you to generate again.
- Puzzles are not stored between visits; seed one you want again.
Privacy and your data
Everything — the layout, the totals and the matching check — happens in your browser. No part of the puzzle or your seed is transmitted or stored.
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