Refraction In Fish Tank - Portable
To illustrate refraction.
Model of fish in plastic water tank.
Due to refraction, the single fish hanging in the corner of the tank, appears to be one, two, or three fish (as in the photograph), depending on the surface(s) through which it is viewed.
K. Eftaxias, C. A. Londos, and F. Vallianatos, An alternative treatment of the problem of image formation of an object through plane or spherical interfaces, AJP 58, 771-773 (1990).