I designed this modular pyramid as a room sound proofing item which is 3D printable and one fits all.
Indicator arrow inside the pyramid is used for assembly of multiple pyramid prints for full wall coverage.
You may print and use this to sound proof your own room.
I hereby give NO guarantee that this will actually work. Thus I will not take any responsibility for failure or misuse.
To fix to a wall, you may use double sided tape, or glue of your choice.
Bare in mind that the pyramid shell is 1mm thick.