# Puzzle 33, I don't get it

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?

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.

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I just did challenge 33 this morning, and I was confused at first, too. After lunch I looked at it again, and it finally clicked: (hopefully this isn’t a spoiler?) you need to use one ball to read the direction of gear bit A (without changing its final direction), then release a second ball to set the direction of gear bit B to match A.

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Hi Guys, its aaaaaages later but just read this topic. It would be great if anyone likes to share his/hers (alternative) solution with me? Eager to learn!
@paul : yours is also very welcome

I am also looking for an educator Guide on puzzle 33. Why is it working with these given pieces? Can it be done with less parts?

I don’t really understand the start conditions. Are we meant to assume that the first ball, either red or blue will go via gear bit B?