In Ursa Tents, your goal is to pitch a tent beside every tree, with no two tents touching and the right number in every row and column.
The rules
Every tree has its own tent, in a square beside it, horizontally or vertically. One tent cannot serve two trees.
Tents cannot touch, not even diagonally.
The numbers beside the rows and above the columns say how many tents each one has.
Every puzzle has exactly one solution, which can always be found by logic alone, without guessing.
Tents and grass
Each tap on a square cycles through its states: empty, tent, grass, and back to empty. Grass marks a square where you know there can't be a tent. Dragging from an empty square puts grass along the path, and dragging from grass removes it. On a computer, right-click to place or remove a tent directly. Grass is just a note: the puzzle is solved once all the tents are in place.
How to solve it
With no tree beside it, a square can never hold a tent: it is grass.
Once a row or column is complete, it takes no more tents: the rest of it is grass. A row with 0 is all grass.
Around a tent, all eight squares are grass.
The last free squares: when a row has as many free squares as tents still needed, all of them are tents.
Paired trees: if the trees beside a square already have their tents, that square is grass.
The squares marked × have no tree beside them: they can never hold a tent.
A tree's last spot: when a tree without a tent has only one free square beside it, the tent goes there.
The corner tree already has grass to its left: its tent can only go below it.
The shared square: if a tree can only have its tent in two squares diagonal to each other, the square touching both is grass: a tent there would block both spots.
The highlighted tree can only have its tent to the left or below. The square marked × touches both: a tent there would leave the tree with no room. It is grass.
Counting by blocks: in a row, two tents are never side by side, so two free squares in a row hold only one, and three hold two (at the ends). When the blocks only just fit the missing tents, each one takes as many as it can.
Row 1 needs 3 tents. The free squares form three blocks: one, two side by side, and one. Two side by side hold only one tent, so each block takes one: the ends are tents.
The impossible tent: if a tent in a square would leave a row or column without room for its tents, or a tree without room for its own, that square is grass.
Row 2 needs 2 tents and has three free squares. A tent in the highlighted square would touch two of them and leave only one. So that square is grass.
The Hint button uses these techniques, starting with the simplest and moving on to the more advanced. It first shows you where to look, and only then what you can deduce.