Gauge Line: 3D Pipe Puzzle

Turn a machine cube in your hands and rotate its pipes until each fluid reaches its matching outlet. Trace a line around an edge, cross an overpass and use fixed valves as anchors. Pipes run across the seams between the six faces, so a route can continue onto the next face.

The 150 levels are in five machines of 30: Boiler, Chiller, Reactor, Distillery and Turbine. Levels unlock in order within a machine, and clearing 20 levels opens the next machine. Each fluid has its own symbol and pattern, so colour is never the only clue. Steam and coolant start on the Boiler. Plasma arrives on the Reactor and oil on the Turbine.

There is no timer and no way to lose a level. A tap turns a pipe a quarter turn. Check lists any leaks or mixed fluids when you ask for it. Stars depend on how many quarter turns you use. Undo and Reset are always available. Each puzzle ends with a short gauge-fill animation.

Stuck? Route one pipe sets the full route of one fluid. You start with three Route Hint tokens and earn one when you first clear every 15th level, up to ten earned in the campaign. Route one pipe can also be earned through a labelled rewarded offer, at most two per level.

The game contains ads and offers in-app purchases. An interstitial ad called Shift break can appear only when you leave the results screen. It never appears before your fourth completed level, never more than once every two completions, and never less than 120 seconds apart. It never appears during play, and leaving a puzzle in the middle shows none. Remove Ads is a one-time purchase that removes Shift break ads; rewarded offers remain. Route Hint ×10 is a pack of ten Route Hint tokens.

The game is for players aged 13 and over. It plays offline. The internet is used only for ads and for purchases through Google Play.