Tents & Trees is a free online logic puzzle, also known simply as Tents. A square campsite is dotted with trees, and your job is to pitch the tents. Every tree needs its own tent on one of its four sides, so trees and tents pair off one to one: a tent cannot serve two trees, and there are always exactly as many tents as trees. No two tents may touch, not even diagonally. The numbers along the top and down the side say how many tents each column and row holds. Tap a square to pitch a tent, tap again to mark it as grass, and drag across the meadow to lay grass on a whole stretch at once. Once a row or column has all its tents, tap its number and the rest of that line fills with grass. Mistakes show up as you make them: touching tents, a tent with no tree, a tree boxed in by grass, a line with too many tents. Every campsite is generated fresh, has exactly one answer, and is proved solvable without guessing before you see it. Eight levels grow from a 6×6 to a 12×12, and the later ones need you to follow a "what if" through to a contradiction. No download, no account.
How to play Tents & Trees
- Every tree needs a tent on one of its four sides — above, below, left or right. Diagonal does not count.
- Trees and tents pair off one to one. A tent between two trees can only belong to one of them, so the other tree still needs its own.
- No two tents may touch each other, not even at a corner.
- The number beside each row, and above each column, is how many tents that line holds.
- Tap a square once to pitch a tent, again to mark it as grass (no tent here), and a third time to clear it.
- Press on a square and drag across others to lay grass on all the empty ones at once. Starting the drag on grass rubs grass out instead.
- When a row or column has all its tents, tap its number to fill the rest of that line with grass.
- Red means a rule is already broken: two tents touching, a tent with no tree beside it, a tree with no room left for its tent, or a line with too many tents.
- On a keyboard, arrow keys move the highlight, T pitches a tent, G or X lays grass, Backspace clears, and Space or Enter cycles the square.
- The campsite is solved when every tree has its own tent, no tents touch, and every count matches.
- Undo steps back one change, Clear wipes the board, and New Puzzle lays out a different campsite on the same level.
- The ? button fixes one square: it removes a wrongly pitched tent first, and pitches a missing one otherwise. Three per campsite.
Tips
- Start with every 0. A row or column with a 0 is all grass, and marking it straight away shrinks the board.
- Any square that does not touch a tree on one of its four sides can never hold a tent. Grass them all at the start.
- Every tent turns the eight squares around it into grass. Mark them as you go and the next forced move usually appears.
- A tree with only one free side left must have its tent there.
- When a line needs as many tents as it has free squares — spaced out so none touch — all of them are tents.
- If every free side of a tree touches the same square, that square is grass, whichever side the tent ends up on.
- In a row that needs one tent between two neighbouring squares, both squares above and below that pair are grass either way.
- On the later levels, pick a square and ask what would happen if it held a tent. If that leads to a broken count or a tree with no room, it is grass.
FAQ
Is Tents & Trees free to play?
Yes. It runs in the browser with no download, no sign-up and nothing to buy. All eight levels are included and unlock as you solve them.
What are the rules of the Tents puzzle?
Place tents so that every tree has its own tent directly beside it (not diagonally), every tent belongs to exactly one tree, no two tents touch even at a corner, and each row and column holds the number of tents shown beside it.
Can one tent belong to two trees?
No. Trees and tents pair off one to one, so there are always exactly as many tents as trees. A tent squeezed between two trees counts for only one of them, and the other still needs a tent of its own.
Can two tents be diagonal to each other?
No. Tents may not touch in any of the eight directions, corners included. That rule is what makes each tent rule out the whole ring of squares around it.
Does every puzzle have exactly one answer?
Yes, and it is checked rather than assumed. Each campsite is built from a real tent layout, then solved by a program that only ever makes forced moves; a board it can finish that way has only one answer. The tests confirm that with an exhaustive search as well.
Will I ever have to guess?
No. A board only ships if it can be finished by deduction alone. On the first levels every move follows directly from a count or a tree; the middle levels need you to weigh every way a row, a column or a tree could still be satisfied; and the last four need at least one "what if" followed through until it breaks a rule.
How many levels are there?
Eight, from a 6×6 campsite to a 12×12. The board grows, and the kind of reasoning each level needs gets harder too, so later levels are not just longer. New Puzzle gives you a fresh campsite on any level you have reached.
Why has a square turned red?
Either two tents are touching, a tent has no tree beside it, a tree has grass or other trees on all four sides and no tent, or a row or column has more tents than its number (or too few free squares left to reach it). A square that is simply undecided is never marked, because an unfinished campsite is not a mistake.
Does it work on a phone?
Yes. Tapping is the whole input, dragging to lay grass works with a finger, and the board scales to the screen so the full campsite and its counts stay visible in portrait.