Calling all who sew, knit, create with yarn thread

The title is based on my impression (admittedly unfounded lol) that this curious storage box is somehow related to storing thread, yarn or some-such! Certainly not old yet I've no idea of use or age. If anyone peeks at this and has an idea what they actually are I'd SO appreciate your insight ! 
I'm stumped.  *top pic is the two halves separated, top and bottom. lower pic (not the best image) is
the two halves put together.*