I am working on a puzzle game with a 6 by 6 grid of storage tanks that are connected to up to 4 tanks adjacent to them via pipes. The gameplay is concerned with combining what's in a tank with an adjacent tank via the pipe than interconnects them.
Right now I store the tanks in a 6x6 array, vertical pipes in a 5x6 array, and horizontal pipes in a 6x5 array. Each tank has a reference to the object that contains both tanks and pipes and when a pipe needs to be animated filling with liquid, the selected tank just calls a method on the container object telling it to animate the pipes it is connected to (subtract 1 from row or column to find connected pipes).
This feels like the wrong way of doing it, as I've also considered just giving each tank references to the pipes connected to it to access directly.