I created these icons using POV-Ray 3.5, a freeware ray-tracer. Like all aqua-look-alike techniques, mine is an approximation of the "real thing", but it is a three-dimensional approximation. Under the simplifying assumption that the observed color of an "aqua" surface is a function of the surface normal, I created such a function and tuned it to get a nice-looking sphere. I then applied it to various other objects, with pleasing results. The functions for "plastic" and "brushed metal" were similar experiments. The icons were assembled and scaled with Photoshop 7.