I've found a YouTube video on how to make sand block entities look like glass, wool, or stairs, etc. I wanted to try and make some sort of creation with it, but the process I came up with involved typing in the name of the block I want it to look like and then placing a bunch of command blocks.
I'm trying to find a system that takes a designated area, scans the blocks to find out exactly what they are (what block, how it's rotated) and places the falling_block entity.
This is what I have for placing the falling_block entity:
summon falling_block ~ ~2 ~ {BlockState:{Name:"minecraft:redstone_block"},Time:1,NoGravity:1b}