About

Pipes Puzzle (also called Net or Network Rotation) presents a grid of pipe segments, each rotatable. Your task is to rotate tiles so that every pipe connects to every other, forming a single complete network from a central source to all endpoints. No pipe can have an unconnected end.

The puzzle is a satisfying constraint satisfaction problem. Some tiles have only one valid rotation; fixing those constrains adjacent tiles, which fixes more, until the solution propagates across the board. Larger grids require more inference steps and occasionally some trial and error.

The hexagonal version (as in the Hexapipes browser game) adds a third direction of connection to each tile, dramatically increasing complexity while keeping the core mechanic identical.

How to Play

• Click a tile to rotate it 90 degrees clockwise.
• Rotate tiles until all pipes connect into a single complete network.
• No pipe segment should have an open end — every end must connect to an adjacent tile.
• The network radiates from a central source tile.

Tips

• Start from corner and edge tiles — they have fewer possible rotations.
• If a tile only has one pipe end, it must be rotated to face an adjacent connected tile.
• Work outward from the source tile, fixing connections layer by layer.

History

Pipe-rotation puzzles have appeared on computers since the early 1990s, with notable examples including Pipe Dream (1989) and Net (the classic screen saver puzzle). The hexagonal variant was popularized by web-based implementations in the 2000s. These puzzles are studied in combinatorics and are related to spanning tree problems in graph theory. The satisfying "all connected" visual when a solution completes has made pipe puzzles a staple of casual game design.