Application of refractive index by special material.
A clock that calculates buoyancy and operates weight.
The denial of the image given by fiction, which keeps moving while floating in water.

These are devices that amplify a specific qualia called floating.

*What is qualia?
“It is “feeling”.
Subjective experiences such as “the red feeling of strawberries”, “the green feeling of the sky”, “the feeling that my head hurts with a hangover”, “the feeling of excitement when watching an interesting movie” Of various qualities. ”
(quoted from wikipedia)