i cannot remember where I learned something about a room shaped like this where if you try to propogate some kind of stuff through it(can't remember if it was sound or light or electrons or what) that like, there will always be portions of the room where the stuff you're propogating won't reach

i can't remember the name of this room or what the experiment was at all I just have this picture in my mind if someone could help I'd appreciate it

ty happy saturday