Ummm I'm not 100% sure but I don't think Blockland actually lets you overlap bricks. It may look like you did, but the brick doesn't actually exist.
nah it'll let you put a brick p much anywhere that makes sense to it and plant it too
oh god overlapping bricks is the most horrid looking thing ever
maybe it's fixed now but in alpha people would make two brick surfaces at the exact same position and the engine couldn't decide which of the faces to render to it just rapidly alternated between the two
yeah this is still a thing
the main thing is that the bricks can't load (floating isn't a prob here ofc) and won't play well with being destroyed by normal means, plus some goofy potential for undesirable placement scenarios. imagine being able to place thousands of bricks that won't cull faces correctly into one spot on top of each other
