Beautiful and fun game with some tricky puzzles. 11/14 took me the longest, that might have been a strong last level, all the following were easier in comparison. What bugged me a bit, was that you have to put down all pipes in order and can't switch out a pipe in the middle. For me it ended up in placing some tiles, then button-mashing undo, placing again, undoing again, ...
But that is just nit picking, I really enjoyed playing it and would continue playing it, if you add more levels.
Edit: And I liked the the grate pun ;-)