Hypertexture

It has always seemed to me that there would be advantages in having optical materials with continually varying density, within which light travels in curved paths. The image on the left is a hypertexture experiment in continuous refraction. The object is transparent, and every point on its interior has a different index of refraction. I implemented a volumetric version of Snell's law, to trace the curved paths made by light as it traveled through the object's interior.

The background is not really an out-of-focus scene; it's just low frequency noise added to a color grad. This is a situation in which noise is really convenient - to give that look of "there's something in background, and I don't know what it is, but it looks reasonable and it sure is out of focus."