Almost got it on my first try (I could've walked to the win but accidentally made a mistake) and thought it was easy. Then it took me 6 or so tries to complete . Funny discovery. Spoiler: How it works As you know, bots can move from unwalkable blocks to walkable ones. So R goes to the slider from the rail... but it goes out of reach. So he autopilots there and repeats the process over and over again.
@Frenzies Spoiler: ... and how it doesn't work Ofcourse if the slider becomes inaccessible, R will stop on the rail. First the rotor was lower, and that made R stop. Also, it only works up to the original position of the slider. I wanted the slider to start in the middle, but it had to be at the end.
A new lesson in Mekorama school! Great compact level, although it's a "trick" level, it's great because it's a discovery level, it takes some moves and taps to reach the right conclusion. Thanks!