Neat and solid level, perfectly mirrored. Want to say, though: and I'm not sure if it's relevant now, but a ball between a wedge and a block will not move after landing there, where as a ball on a block can move around and spin. B doesn't mind, but it can result in a ball getting rolled out of the spot you intended it to land, and can also result in instability if R or L were to cross it. I haven't played your other levels and if this is something you already knew about then sorry for being presumptuous! Those moves to go back were tough to time right! I wish I could give 4.5 stars.
As your previous level the tricky gameplay is pretty easy but as I am in love with your symmetrical design I decided to add a star... thanks for sharing & for the fun @Robot B
