Sometimes people may intend to use one ModTer inside of another to give more colors...?
Planting one modter in another (or any brick that can't normally be placed in another) doesn't work with this mod. The implanted bricks are visible but they can't have collision, they don't save, they're only visible to players who were on the server when it was planted, and they go away (from your perspective) if you rejoin the server.
The only real use of the mod is to make floating bricks