Pipes Puzzle Online
Rotate every pipe tile until there are no leaks and the entire board becomes one connected network. Practice on deterministic 5×5, 7×7 and 9×9 boards generated locally from verified spanning-tree networks, with live power flow, orientation candidates, locks, Undo/Redo and a technique-aware Verified Hint.
How the Pipes puzzle works
Each cell contains a pipe shape: an endpoint, a straight segment, a corner, a three-way junction or a four-way junction. You may rotate the tile, but you may not change its shape. A solved board has two properties at the same time. First, every open pipe end must meet an open pipe end on the neighboring tile, so nothing leaks into a wall or into a closed side. Second, every tile must belong to one connected network. Matching local edges is therefore necessary but not sufficient: several small closed components are still unsolved.
The center tile is used as a visual power source. As you rotate tiles, the board highlights the portion that is currently connected to that source through reciprocal pipe edges. The Powered counter is not a second rule; it is a fast way to see how much of the one-network requirement is already satisfied. A board is complete only when all cells are powered and there are no mismatched or boundary-facing ends.
Practice is deterministic. If you open a no-seed Practice URL, the page stabilizes it with an s= value. Reopening that URL gives the same verified source, symmetry transform and scramble, which makes a difficult deduction replayable instead of disposable.
Start with borders, corners and tile degree
Boundary information is the fastest safe deduction. A tile on the top row can never point north; a left-edge tile can never point west. Corners remove two outward directions at once. Endpoints and straight pieces near a boundary therefore lose orientations quickly, and a corner pipe in a board corner may become forced immediately.
Tile degree matters too. An endpoint must connect to exactly one neighbor. A three-way junction must connect to three. The shape is fixed, so orientation is the only unknown. When a neighboring tile is locked or has only one legal orientation left, its open and closed edges constrain the adjacent domains. V0.128 propagates these relationships repeatedly rather than checking only the tile you just touched.
The live candidate monitor surfaces cells with one or two remaining legal orientations under the current boundary and lock assumptions. A one-orientation tile is a genuine forced deduction under those assumptions. Two-orientation tiles are useful pressure points, but they are not automatically safe guesses.
Locks are pencil marks, not hidden answers
Use Lock/Unlock when you believe an orientation is established. On desktop, right-click toggles a lock directly; the Lock tool provides the same action for touch users. Locks are deliberately treated as your reasoning state. They are not solution clues baked into the source bank, and the generator does not need pre-locked answer tiles to make the puzzles unique.
This distinction matters for trust. The independent verifier receives only the un-oriented tile shapes and board dimensions. It then counts legal orientation assignments that satisfy boundaries, reciprocal edges and whole-network connectivity. Only sources with exactly one legal network enter the frozen bank. Locks created while you play are never used as evidence that the original puzzle was unique.
If a lock creates an impossible local domain, the Contradictions monitor can expose the dead state. Undo lets you recover the previous reasoning state without restarting the puzzle.
Use the powered network without chasing the glow
The power visualization is excellent feedback, but maximizing the glowing region is not itself a proof. A rotation can temporarily connect many cells while forcing an impossible edge elsewhere. Use power as a connectivity diagnostic after applying boundary and orientation reasoning, not as a substitute for it.
A productive workflow is: force obvious border orientations, lock only deductions you trust, inspect cells with small remaining domains, then use the powered frontier to see where a disconnected component must eventually join. Junctions near that frontier are often informative because their open sides constrain several neighbors at once.
V0.128 computes the powered component once per board analysis and shares that result with rendering. That keeps the live visualization responsive even on 9×9 Challenge boards instead of traversing the network separately for every displayed cell.
What Verified Hint actually does
Verified Hint first looks for a tile whose orientation domain has collapsed to one choice after boundary and locked-neighbor propagation. When such a cell exists, the hint uses that forced orientation and explains why it is forced. If no locally forced tile is available, it chooses a low-domain unresolved tile and reveals its orientation from the independently verified unique solution.
Using Check or Verified Hint marks the run Assisted. Clean and Assisted records stay separate so a player can learn with support without presenting the result as an unaided solve. Hint therefore exists as a teaching and recovery tool, not as an invisible auto-solver.
Keyboard players can move the active cell with the arrow keys, rotate with [ and ], toggle a lock with L, and use Enter or Space for the selected tool. Undo/Redo are available from the controls and standard keyboard shortcuts.
Why these boards are independently verified
The project-local generator builds candidate networks as spanning trees, derives each tile shape from the tree edges and hides every orientation. A separate orientation solver then receives the shapes without trusting the stored answer. It enumerates legal orientations, applies boundary and edge-consistency constraints, requires one connected network and counts solutions. Multi-solution seeds are rejected rather than patched with answer locks.
The frozen V0.128 bank contains 60 sources: 20 Easy 5×5, 20 Standard 7×7 and 20 Challenge 9×9. Eight square symmetry transforms are supported, yielding 480 verified transformed starts before deterministic scrambles. Release verification separately re-counts all 60 source boards and all 480 transformed boards, then samples 6,000 deterministic Practice starts and replays their stored solutions.
This provenance is intentionally local. There is no remote puzzle API, scraped puzzle pack, paid solver or runtime account requirement. The browser downloads the frozen assets with the application and can replay the same seed locally.
Practice, Daily and repeat play
Practice is for unlimited replay and seed sharing. Daily Pipes selects one verified board from the same frozen source system using the date, keeps its history and streak locally, and remains separate from the platform's frozen Today’s 6 rotation. Adding this specialist therefore does not silently change an existing daily sequence.
Autosave stores the current rotations, locks, move count, elapsed time and Undo history in browser-local state. Restart lets you retry the same start; Fresh gives Practice a new seed. Pause stops the timer and hides the board. No account is required.
If you are new to network-rotation puzzles, begin with Easy and deliberately use locks so the orientation monitor has meaningful assumptions to propagate. Move to Standard when you can distinguish local edge matching from global connectivity, then Challenge when 9×9 junction interactions feel manageable. The goal is not rapid clicking; it is turning each rotation into an explainable deduction.