Meet the source. Then explore.

Sixteen channel tiles stand between an inlet and an outlet. Rotate each one a quarter-turn to join its openings with its neighbours. The coloured flow shows how far the source can currently reach.

1. Meet the source

   The inlet enters tile 1 from the left. Rotate that tile until one of its openings faces the inlet.

2. Match two neighbouring edges

   Each connection needs an opening on both sides of the boundary. A closed neighbour stops the highlighted flow.

3. Turn one quarter at a time

   Activating a tile rotates its channel clockwise by ninety degrees. Read the new opening labels after every turn.

4. Release the current

   Connect through tile 16 and out of its right side. New waterway scrambles the rotations of a board with a valid route.