Page "Guitar" Paragraph 36

The electric bass guitar is similar in tuning to the traditional double bass viol.

Hybrids of acoustic and electric guitars are also common.

There are also more exotic varieties, such as guitars with two, three, or rarely four necks, all manner of alternate string arrangements, fretless fingerboards ( used almost exclusively on bass guitars, meant to emulate the sound of a stand-up bass ), 5. 1 surround guitar, and such.