Voles.

The meadow is flooding. Each number is a vole family and says how big their island is. Shade the water so that every island has exactly one number and that many cells, islands never touch by a side, all the water connects, and no 2 by 2 block is all water.

An island is a group of dry cells that hang together side by side. The number counts the cell it stands on as well, so a 1 is a family on its own and everything beside it is under water. Two islands may sit corner to corner, never side by side, otherwise they would be one island with two numbers.

Every meadow has exactly one way the water can lie. When the last cell is right, the game notices by itself.

Tap or click a cell to flood it, tap it again for a dot, which is your own note that the cell stays dry, and once more to clear it. Hold and drag to shade a run of cells at once; a drag that starts on a dot rubs marks out instead. Only the shading decides the puzzle, the dots are there to help you think. Nothing lights up while you play: finding a mistake is part of it.

Check first tells you only how many marks are wrong and in which rows; press it again and it marks them. Hint names the rule and the place without saying what goes there, and the second press fills that one cell in and explains it. If something on the meadow is already wrong, the hint points there first. Hints and checks are free and counted, and shown when you finish. Clear empties the meadow; the clock keeps running and one Undo brings everything back. Copy result shows up once the meadow is solved and copies a short line about the day, your time and the help you used, with nothing in it that gives the solution away.

Keyboard: arrows move from cell to cell, Space or Enter takes the cell through water, dot and empty, W floods it, X puts a dot, Delete or Backspace clears it, Escape lets it go, U or Ctrl+Z undo, R or Ctrl+R redo, P pauses.

The clock runs from your first mark to the last cell and pauses when you leave the tab or sit still for a minute, which also hides the meadow. Your progress, time, history and day streak stay in this browser, and in your account when you are signed in, so you can continue on another device. The day turns over at midnight, Bratislava time, so everyone gets the same meadow on the same day.

Monday and Tuesday are easy (six by six), Wednesday and Thursday medium (eight by eight), Friday and Saturday hard (ten by ten) and Sunday is the challenge: twelve by twelve. The week strip under the meadow takes you to the other days; the archive goes back a year, and the practice sets have eight meadows of each level with no date attached.

Difficulty is measured, not guessed. Every meadow is solved by a program that only knows named rules, in three layers: the plain ones (a 1 is a family on its own, a cell between two numbers, an island that already has all its cells, a cell no number is close enough to reach, three cells of a two by two block already flooded), the ones that look further (an island with a single way to grow, a piece of water with a single way out, a cell that would join two families or overgrow an island), and the hard one (trying a cell both ways and dropping the one that ends in nonsense). Easy and Medium never need that third layer; Sunday leans on it the most.

Start with the ones. A 1 has its whole island already, so all four cells beside it are water, and that is free ground everywhere on the meadow.

A cell that sits between two different numbers, side by side with both, is always water: one cell cannot belong to two families at once. The same holds for two numbers standing corner to corner, because the cell between them touches both.

Count how far a number can reach. A family of 3 can never lie more than two cells away from its number, so anything further off, with no other number near, is under water.

Water never fills a whole two by two block. Once three cells of such a block are shaded, the fourth is dry, and a piece of water with only one way out has to take it, because all the water hangs together.