Puzzle 33, I don't get it


#1

I can’t figure out what I’m meant to do in Puzzle 33. As it’s written it seems trivial to just run the balls through and solve it.

What’s the constraint or detail that I’m not appreciating from the book?


#2

I’m not sure what you mean by “just run the balls through and solve it”, since you could say that about any of the puzzles. You need to set up the board somehow, and choose a specific lever as the start lever. Now, if I set both bits to the left, at the end, they are still pointing left. If I set both bits to the right, at the end, they are still pointing right. But if I set them differently, then after the computation is done, they both have to be set the way A was pointing. So, there are four test cases (which are shown in the examples). I’m not sure if this clarifies anything.