A type, or style, of keys found on a keyboard that does not have extruding lips or edges. Waterfall style keys (also known as “Square Front”) are best recognized as the key found on the famous Hammond B3 organ. Many B-3 players perform using the palm of their hands on the base of the keys in a “wipe” motion up the keyboard (glissando). This, and other performance styles, are made possible by Waterfall keys. Common, sharp-edged synth keys would make this performance style difficult or impossible.