This is a fun little experiment relating to compliant mechanisms (though this one does rely on one moving part: the marble).
If you've seen my Cool Prints video about it, you know this doesn't function 100% as intended, but it's still pretty cool!
Print at about 4 shells, 35% infill. I used PLA, though other filaments may have better results. Print includes a small helper disc at the end since bed adhesion can be a challenge with a long thin part like the chopsticks. You can just rip that off after printing or clean it up with an Xacto knife.
Add one standard 9/16" (14mm) marble as the pivot point.