If it fits...

Nice use of a somehow familiar trick, with some nice logic

Hooray! Victory at last, very nice puzzle!

Thanks for the ratings @richardfu_ and @Star Penguin!

Forgot about that trick . Once rediscovered, the logic was already understood. Still requires some delicate handling, and strict order of steps. Good challenge!

I had not seen the video of the solution before solving the puzzle. I normally skip all puzzles for which the solution has been given. Watching those solution videos is nice but solving the puzzles is not much fun because they are excessively complex. This puzzle can be solved without any hints and the solution even looks very easy in the video.

Thanks for the rating @GFJ. The video is there in case you were stuck in one step, you can watch the whole thing or just part of it to confirm that you're doing it right.
I'm trying to create more levels that require logic instead of ability so in that sense all the steps should be easy to reproduce but the order of the steps may not be obvious to some so that's why there's a video.
What I'm trying to say is, I hope you won't skip levels just because there's a video for it, you may be missing some really good levels .

Thanks for the ratings @cpw and @Block builder!

Cute. I'm not sure what purpose the ball serves, though.

Great level! Very nice logic steps although I had some difficulties with the mechanism... Thanks!

@D.S.Masters I wonder how you solved it without it...
Did you watch the video?

@Chuckthulhu I got the first few steps figured out, and then I had to resort to the video. The ball becomes part of the mechanism?

@D.S.Masters

Spoiler: The ball...

pushes the metal structure in the left side so B can go to the back alley...

@Chuckthulhu Ah, okay... that makes sense.