Did these for a friend but I'm sure I'll get the chance to use the idea again myself.
All these do is to cover up the hole where the radiator pipes pass through some bathroom tiles.
Originally these were designed as two pieces that fit loosely around the pipes but it seemed better to print them as one large piece plus a small section that slotted in.
The 30 deg. cut V slots are 0.2mm wide which allows the parts to be broken cleanly after printing.
I suspect I could make this slightly wider as they are very close fit:-
Assembled, the join is almost hidden:-
Here is one being fitted to the radiator:-
Final result :-