I usually test materials, how far they can go, what I can do with them, how tolerant and forgiving are for hammering, brazing, fire, how they look to me; test ideas that later will be transferred into larger pieces or set aside to think more about it.  I used to incorporate prototypes into jewelry since they are cool, functional and work great but also enjoy sharing parts so we all can play and add them to bundles I make as destash for you all.
This destash has a couple of those prototypes: the bottle shaped cage and the nickel silver prongs setting for the stone rustic bead and a copper set river stone pendant.
They measure approx. 60 x 52mm, 67 x 34 x 11mm, 31 x 23 x 10mm