Hmm, how do you make a box that is on ALL 3 layers?

[Ming-Yan]

That might lag stuff a little, nah, I'd rather make the other bricks non-collidable in the same layer.

Buildism has no lag. I can spam 1000 blocks in Grey world and it still runs 100%.

3 blocks isn't gonna do anything. Manually putting stuff in layers is something you learn is more efficient when making a full game. (because if your script has a hole, you will have to do a lot more work)