before you print, i would recommend shrinking just the length of the pendulum arms by 75% or more, as i had issues with the 2nd arm hitting my wall.

this is a double pendulum that is attached to your wall.

prepare:
what you need is, 4 2" deck screws.
4 to 5 ball barrings which can be bought here https://amzn.to/3c0mZnv for $7.
print the long pendulum with 60 - 100% infill at .2mm resolution
print the pendulum separator with 100% infill at .2mm resolution and supports
print the screw with 100% infill at .2 - .12mm restitution and rafts (breaks somewhat easily)
print the short pendulum with 50 - 100% infill at .2 resolution
print the wall mount with 100% infill at .2mm resolution

assembly:
take the longer pendulum and 2 ball barring and insert the bearings into the pendulum (you'll probably need to use a tiny amount of glue the get then to stick use hot glue if available.) Then do the same thing for the smaller pendulum. You will need the sand down the pendulum separator in order for it to fit into the baring's. Drill 4 hols into the wall mount base that are at about the 12, 3, 6, 9 positions. Then find a stud in the wall and make sure you have enough space (the radius of the double pendulum is 58cm or a bit less then 2 feet) then attach the wall mount to the wall using the 4 deck screws. Attach the long bar to the wall mount screw in the screw a bit more then finger tight (the screw can break if you tighten it to much.)

the screw will break eventually.

have fun!