Water 0 / 0
Free online pipe puzzle
Pipe Flow is a puzzle of plumbing. The board is covered with pieces of pipe - caps, straights, elbows, tees and crosses - all turned the wrong way. Somewhere among them sits a tap. Tap a piece to turn it a quarter clockwise, and when two neighbouring pipes open onto each other, the water passes between them. The puzzle is solved when the water has reached every piece on the board.
A new board every time
No board is ever repeated by design: each one is generated when you start it. The generator grows a branching network of pipes outward from the tap, turns every piece to the shape it needs, and only then spins them all at random. Because the board is built from a solution, it can always be solved - and the board number shown above the pipes is the seed that makes it.
Three difficulty levels
| Level | Board | What to expect | Points |
|---|---|---|---|
| Easy | 5 × 6 | About two dozen pipes in long runs, with a few gaps in the grid | 1 |
| Medium | 6 × 8 | Around forty pipes, more branches, almost no empty cells | 2 |
| Hard | 8 × 10 | Eighty pipes, every cell used, many tees and crosses | 3 |
Made for the phone
The whole board is one big tap target per piece, so there is nothing to aim at. Undo takes back as many turns as you like, Hint turns one wrong piece into its correct position and locks it, Lock marks the pipes you are sure of so a stray tap cannot spoil them, and Restart scrambles the same board again. The pipes light up as the water reaches them, with a small splash of sound you can switch off. On a computer, click a piece, or right-click to turn it the other way, and move between pieces with the arrow keys. Light and dark themes follow your device, and the board in progress is saved as you play.