The steel guitar originated in Hawaii, credited to Joseph Kekuku, who began sliding a piece of metal across the strings of a guitar. This 'slide' technique allows for smooth glissandi and microtonal 'whining' sounds. The instrument is played horizontally on the lap (lap steel) or on a stand with legs. In the 1950s, the 'pedal steel guitar' was developed, adding foot pedals and knee levers that change the pitch of individual strings while playing. This made the instrument one of the most complex in the world, often called 'the guitar that's also a machine.' The pedal steel is the defining sound of modern Country music and Hawaiian music, but it has also appeared in Pink Floyd's psychedelic rock and African 'Juju' music. Its ability to bend chords and notes simultaneously gives it a unique, crying quality that is instantly recognizable.