Pipe puzzles come in two main kinds. In rotation puzzles, every tile is already on the board and you turn them until all the pipes join up. In placement puzzles, like Heat Lines, you lay pieces from a hand onto an empty board to build a route from a source to its targets. The tips below work for both, and each one says when it matters most.
First: know your pieces
Most pipe games use the same four shapes, sometimes under different names.
- Straight
- Corner (elbow)
- T-junction (tee)
- Cross
A straight joins opposite sides, a corner (or elbow) turns 90 degrees, a T-junction (or tee) splits one line into two, and a cross joins all four sides. Knowing how many openings each one has is the key to most of the tips below.
1. Start with what can't change
Begin at the parts of the puzzle with the fewest options: the edges and corners of the board, tiles next to walls or rocks, and the source and targets themselves. In a rotation puzzle, a pipe on the edge can never point off the board, and a corner tile in a board corner often has only one possible rotation. In a placement puzzle, a target tucked between two obstacles may have only one side a pipe can reach.
2. Find the forced moves
Before trying anything clever, look for spots with only one sensible choice. Fix those first, then look again: each forced move usually removes options from its neighbors and reveals the next one. Good pipe puzzles are built so that a chain of small certainties leads to the solution.
3. Work backward from the hardest target
Find the target that is hardest to reach: the one farthest from the source, or the one with the fewest open sides. Plan its route first, then connect the easier ones to that line. Routes to easy targets are flexible, so they can bend around a route that has no choice.
In Heat Lines: a lodge needs heat from two different sides, so it is almost always the hardest target. Plan the fork that reaches it before anything else.
4. Keep the main line short
Every extra bend costs a piece, and in many games pieces are limited or count toward your score. Look for the straightest path first, and only take a detour when an obstacle forces it. Counting the tiles between the source and a target tells you the fewest pieces that route can possibly use.
5. Branch to share a route
When two targets lie in the same direction, don't build two separate lines from the source. Run one main line toward them and split it with a T-junction or a cross near the point where their paths would part. Sharing the trunk is the single biggest saving in most placement puzzles.
6. Watch every open end
In rotation puzzles, every opening must meet another opening, so a pipe pointing at a wall or an empty tile means something is wrong. Count the openings around a tile to see which rotations are even possible. In placement puzzles like Heat Lines, open ends are allowed, but each one is a piece that isn't carrying heat anywhere useful.
7. Look at the pieces still to come
If the game shows your next pieces, read them before placing anything. A corner you need may be two pieces away, and a straight placed now might be better saved for a long run later. Plan a few moves ahead with the pieces you'll actually have, not the ones you wish you had.
8. Park awkward pieces
Sometimes the piece in your hand has nowhere useful to go yet. Many games give you a way out: a hold slot to keep one piece for later, or the option to replace a pipe that isn't connected yet. In Heat Lines, you can drop a new pipe on any placed pipe that doesn't carry heat yet, so a parked piece out of the way can be swapped out later.
9. Don't wall yourself in
A route that hugs the middle of the board can cut it in two and leave a target unreachable. Before you commit to a line, check that every target you haven't connected yet still has a free path to it. Routing along the edges often keeps the middle open for later branches.
10. Turn obstacles into guides
Rocks, walls and blocked tiles look like problems, but they remove options, and fewer options make a puzzle easier to read. Use them to decide where a line must bend. Some obstacles change during play: in Heat Lines, ice melts once heat reaches the tile next to it, so bring the heat beside the ice first, then build through.
11. Use what's already on the board
Pre-placed pipes are free pieces. Before planning a new line, see whether an existing pipe already points the right way, and build your route through it. When it points the wrong way, plan around the direction it forces rather than fighting it.
12. Restart early, not late
If a route has gone wrong, a fresh start is often faster than undoing piece by piece, and you'll see the board with new eyes. Try the mirror image of your first idea, or start from a different target. Many players solve the hardest levels on the second or third clean attempt.
Practice on today's puzzle
The best way to get better at pipe puzzles is a little practice every day. Try today's daily pipe puzzle in your browser, or read the Heat Lines guide for every rule of the game, from ice blocks to two furnaces.