LaserTank set. I just solved it now, but it took me a while. My
score is 176 Moves / 61 Shots while the GHS I currently have says 168
Moves / 59 Shots.
Obviously you need to use 3 blocks to get across the 3 waterways. You
will need to use the other block to allow the tank to rest on
conveyors twice. This means that the block that is in the outer most
waterway must be placed judiciously. You will need to shoot an
anti-tank from the side, a mirror from behind, and another anti-tank
from behind.
I hope that is enough of a hint for you. Good luck, and have fun!