Anyway, just see following youtube!
It seems simple but making it quite small is so surprising, and the motion is very funny!
If you want to buy, here below you can buy it directly from Japan.
If this is the first time to buy from Rakuten Global refer http://domoarigatojapan.weebly.com/blog/how-to-use-rakuten-global-service But maybe not needed because it's easy to do.