Mosaic Art

According to the extremely credible and always accurate Wikipedia, a Mosaic is the art of creating images with an assemblage of small pieces of colored glass, stone, or other materials. It may be a technique of decorative art, an aspect of interior decoration, or of cultural and spiritual significance as in a cathedral. Small pieces, mostly roughly square, of stone or glass of different colors, known as tesserae, (diminutive tessellae), are used to create a pattern or picture.
Mosaics have existed since the days of the ancient Greeks and Romans, and well before, some dating back to 1500 B.C.E., and are still made today, by artists such as Invader.
Mosaics were often used for religious purposes.

Here are some examples of mosaics:

Note the heavy religious influence, as well as the emphasis on yellow, brown, and green.