Standing at Y255 I places 2x2 square of mangroves root at Y256. I then placed 6 logs 2 on each side crouching. I jumped up to Y256 and was still crouched. I tried to place logs on the edge on the last side by handing over the edge and clicking on the edge of the mangrove root. I took 6 full of suffocation damage and saw air graphic flashing fast.

I tried to eat to replenish my hearts as I was crouched at y256 and I dropped through the mangrove roots to Y255.

I un-crouched to stand and jumped back to y256 crouched and was able to place the blocks.