A tip for a correct elevation: Tap on the nearest grass block near the lift, wait for all possible mechanism pulsations and tap on the elevator. -Edit- Spoiler: Video
In case you were wondering... Spoiler: Mechanism It's a proximity sensor I couldn't add any sliders and motors because they would have changed sensor functions(proximity sensor are very sensible). When you go down, using stairs, the mechanism trembles because it's heavy, It's not a sign of bad quality; On the contrary, I made sure that the mechanism was as efficient as possible. Look for any possible traps,don't forget any path and.. Good Luck!
@meko a question before rating... Spoiler One ball is a trap,right?Or B can push it and with autopilot B can go to the last zone ...
@delator77 Yes,and Spoiler In this case intended path is more simple then autopilot way,so there is no shortcut
@Block builder Spoiler: Working Mechanism It works because the lift goes down when B is near it. But the sensor doesn't see him when B it's one block higher or lower. And it works even if B is ON the elevator.
And thanks to @chemi @Jóh @huijiuggbf @Mse&Csani for giving me four special likes.. Now I've reached 1000 likes!
Thanks @laurence.gr ,It wasn't easy to build the level because I couldn't add any sliders or motors to make it more complex.