Laser Tank

Me again. Need help again.
On Level 380 I've managed to get two blocks across the water; But any solution I can devise needs four.
Where am I going wrong? Thank you

Two blocks are all you need as long as you build your bridge next to one of the ground spaces in Row 8 (ie Col D, G, I, or M). That will allow you to push a block across the bridge and then to the side so that it doesn't interfere with the passage of the second block.

Then you use those two blocks to allow you to get past the two ATs in Row 6 and then just push those ATs down to recover the blocks to reuse.