This must be one of those Japanese "quirky-fun, but useless inventions" things (chindogu). You know, like the toilet paper holder you strap to your head so you're never without a roll, or the vise you use to press two or more well-worn bars of soap together into a single, bigger bar.

In terms of design it reminds me of that bit of Animusic's "Pipe Dream" where xylophone bars of the appropriate pitch travel on a rail just in time to be struck by ball bearings from a stationary launcher: https://www.youtube.com/watch?v=HmoUSSVSV7I&t=2m12s