Hi there, There is one trivial exercise in chapter 12 <List Monad> saying 1. As an exercise, you can change this function so that when you can reach one position from the other, it tells you which moves to take. 2. how to modify this function so that we also pass it the number of moves to take instead of that number being hard-coded. I have one answer (find the URL below) but I'm not happy with it. https://github.com/freizl/dive-into-haskell/blob/master/monad/knight-queue.h... Do you have better ideas? thanks. -Haisheng