Name that object...please?

We were delighted to host a study visit from the All China Youth Federation today.

We are however a tad confused by one of the gifts they generously gave - and didn't manage to ask for an explanation before they left!

It's made of china, with Chinese masks painted on...and on first glance looks just like a jar. However, it sits on a wooden base...and spins!!

It's very clearly MEANT to spin - designed that way. But we cannot fathom why.

Anyone out there who can help?