Project Delphis: Mystery of the Silver Rings
The young dolphin gives a quick flip of her head, and an undulating silver ring appears--as if by magic--in front of her. The ring is a solid, toroidal bubble two feet across--and yet it does not rise to the surface! It stands erect in the water like the rim of a magic mirror, or the doorway to an unseen dimension.

physics based toys made by dolphins. way cool.