[lvuhuxtd] 3D layers

adapt the feature of "layers" of 2D drawing programs into a 3D design program.  this has likely already been done.

move stuff between layers.  translate an entire layer.  duplicate and delete layers.

provide such a feature in Minecraft.  inspired by the nether: what if the nether were more useful for building stuff in the overworld, even in creative mode?  store partially built stuff there, which can easily be fetched.

a stack of many 3D layers almost feels like 4D.  however, layers can be reordered, and one can't do 4D rotations.