Pipe Twist

Pipe Twist is a plumbing puzzle. Every square holds a piece of pipe — a straight, a corner, a T-junction or a dead end — and every piece has been turned to a random angle. Tap a piece to rotate it a quarter turn.

Water starts at the blue tank in the centre and flows through any pipes that join up properly. Pieces that are connected to the tank light up blue. When the whole board is blue the network is complete and a larger one appears: the grids grow from 4×4 to 7×7. A good method is to begin with pieces on the edges and corners, where fewer positions are possible.

Rotate pieces so that all of them connect to the central tank. Your score is the number of networks completed.