puzlo › Dripline › Strategy guide

How to solve Dripline

Dripline looks like a puzzle about turning pipes. It is really a puzzle about ruling out the turns that can't work. Here is how to do that, with a real board solved at the end.

The rules in one minute

The board is a grid of pipe pieces with a water source in the middle. Some pieces start turned the wrong way. Tap a piece to turn it a quarter turn clockwise. Water flows through every piece connected to the source, so you can see your network grow in blue.

The puzzle is solved when every piece is connected to the water and there are no leaks: no pipe end may point at a wall, at the edge of the board, or at a piece that doesn't connect back.

One more fact makes the logic much easier: each board is a single network with no loops. Water can only reach any piece by one path. You will use this later.

Know your four pieces

A straight piece has only two different positions (across or up-down). Ends, corners and T-pieces have four. That is why straights are the easiest pieces to place, and a good place to start.

The logic that solves most boards

1. Nothing points off the board

No pipe end may point outside the grid. On the edge of the board, a straight piece must run along the edge, and a T-piece must have its flat side against the edge. In a corner it is even stricter: a corner piece has exactly one position that fits.

2. Start from the pieces that are already right

Many pieces start in their correct position. When the water already flows through a piece and its open ends line up with neighbors, it's probably done. Work outward from the water, and look for pipe ends that meet nothing: one of the two pieces at that spot needs turning.

3. Dead ends never meet

If two end pieces pointed at each other, they would form a closed pair that can never reach the water. So two neighboring end pieces must point away from each other. The same idea works for any small group: if a few pieces would close into their own little network, at least one of them is wrong.

4. No loops

Because the network has no loops, four pieces around a square can never all connect to each other in a ring. If you find yourself building a ring, one of those connections must be broken.

5. Decide before you touch

Tapping the same piece several times in a row counts as one move, but coming back to a piece later counts again. So work out where a piece has to point before you turn it. Sure moves first, guesses last.

A worked example

This is a real 4×4 board, the size you get on Mondays. The water is in the drop-shaped source. Pieces in blue are already connected; grey pieces are not.

Here is how to find them without guessing. Start with what the edges force. The bottom-right corner holds a corner piece, and a corner piece in a corner has only one position that points into the board: up and left. Along the right edge, the straight piece in row 2 must run up and down, and the T-piece in row 3 must keep its flat side against the edge. Both already do, so leave them alone. Then follow the water outward from the source: wherever a blue pipe end points at a piece that doesn't answer, turn that neighbor until it does, and check that its other openings still have somewhere to go. Use dead ends never meet and no loops to settle the last few pieces.

Moves, par and stars

Par is the number of pieces that need turning in the game's own solution. Each piece you adjust counts as one move, however many taps it takes in a row. Finish within par for three stars. Sometimes a board can be connected in more than one way, so beating par is possible, and earns a trophy.

Boards grow from 4×4 on Monday to 6×6 on the weekend, and on harder days more pieces start out of place. The same edge-first approach works on every size. Practice mode has unlimited boards with hints if you want to train.