How to play Pipes
The rules fit in one sentence, the techniques take a page. Every puzzle on the site can be solved with the steps below, without guessing.
The goal
The board is a network of pipes with every tile turned at random. Rotate the tiles back so that the pipes join into one network: water from the pump must reach every lamp, no pipe may point at nothing, and the pipes must not close into a loop. A lit lamp and the blue water show how far the pump already reaches.
Four kinds of tiles
A lamp is the end of a pipe and has one arm. A straight pipe has two opposite arms and only two different positions. A corner has two arms at a right angle, and a tee has three. Rotating a tile never changes its kind, only where its arms point.
Controls
- Click or tap a tile to rotate it clockwise; Ctrl+click rotates it back.
- Right click or long press pins a tile: it turns grey-blue and no longer rotates. Pin every tile you are sure of, and stray clicks cannot spoil the work.
- Undo and redo take back moves and pins; “Start over” returns to the first position.
- With the keyboard: arrows move the cursor, Space or Enter rotates, P pins.
Techniques
Each technique fixes a tile, or at least rules out some of its positions. Pin what you have fixed, and the next technique has more to work with.
Nothing points off the board
A pipe may not point past the edge. That alone fixes many tiles on the border: a corner in a corner of the board fits only one way, a straight pipe along an edge must run along it, and a tee on an edge must turn its back to it. Start every puzzle here.
Two lamps never face each other
Two lamps joined to each other would make a tiny network of two tiles, cut off from the rest. So a lamp next to another lamp must point elsewhere. The same goes for any small group: if it closes up before it reaches the pump, it is wrong.
No loops
The network is a tree: there is exactly one way along the pipes between any two tiles. So if two tiles are already joined by one route, the pipes between them may not join them a second time. Look for corners that would close a ring and turn them away.
The last way out
A group of connected tiles that does not yet hold every lamp must keep growing. If only one of its tiles can still lead out, that tile must point out of the group. This step, together with “no loops”, is what unlocks most puzzles in the middle of the board.
What if
On Hard, now and then no simple step helps. Then pick a tile with two possible positions and try one in your head: if it would make two lamps face each other, close a loop or leave a group with no way out, the tile must take the other position. You never need to guess further than one step: every puzzle is checked to be solvable this way.
Wrap around
With Wrap around on, opposite edges are joined: a pipe that leaves the board on the left comes back on the right, and the same for top and bottom. The edge technique is gone, so start with lamps and with tiles whose neighbours are already fixed. The dashed frame of the board reminds you that the mode is on.
Colors
With Colors on, the board has two or three pumps. Each pump must reach every lamp of its color, and networks of different colors must never join: where two colors meet, the water turns murky. The pipes are grey until water reaches them, so part of the puzzle is working out which network a pipe belongs to. Two new rules help: pipes between pieces of different colors stay apart, and a network that already holds its pump and all its lamps takes nothing more.
Difficulty levels
Easy: the edges and simple steps are enough. Normal: the puzzles are picked so that you get stuck two or three times and need “no loops” or “the last way out”, and each such step opens a stretch of the board. Hard: some steps need a short what-if.
Tips
- Work from the edges inwards, and pin every tile as soon as you are sure of it.
- The lamp counter above the board tells you how much is left.
- Stuck? Look for a group of tiles with only one way out, or a corner that would close a loop.
- Blue water only shows what is joined to the pump. A tile can be right before the water reaches it.