Wall-fountains run the gamut from classical Greek figures and wall mounted gargoyles to sleek modern art forms and spouting frogs and fish. A wall fountain usually spills water through--such as a mask or a decorative plaque--into a basin which hides a small pump. The statuary can be terra cotta, plastic, fiberglass, cast concrete (often designed to mimic terra-cotta or stone), or metal. Stone and cast-concrete wall fountains require a wall strong enough to support their weight, as well as sturdy, well-secured mounting hardware.