Dolphin version

This is the design that has been placed into the tank with the dolphins at the National Aquarium in Baltimore, Maryland's largest tourist attraction. It is based on the "rocking tray" design (see below), but it also has a protective box built around it, and a "box of air" mounted below it as the air supply. The dolphins absolutely love it, and race each other to see which one can be the first to bite the bubble ring when it comes out.

Here's a picture of the device itself. My first patent covers this design.