G also uses the soprano sax as his principal instrument. Saxophonists such as John Coltrane, Ornette Coleman, Sam Rivers, and Pharoah Sanders defined the forefront of creative exploration with the avant-garde movement of the 1960s. The new realms offered with Modal, harmolodic, and free jazz were explored with every device that saxophonists could conceive of. Sheets of sound, tonal exploration, upper harmonics, and multiphonics were hallmarks of the creative possibilities that saxophones offered. One lasting influence of the avant-garde movement is the exploration of non-Western ethnic sounds on the saxophone, for example, the African-influenced sounds used by Sanders and the Indian-influenced sounds used by Coltrane. The devices of the avant-garde movement have continued to be influential in music that challenges the boundaries between avant-garde and other categories of jazz, such as that of alto saxophonists Steve Coleman and Greg Osby. Some ensembles such as the World Saxophone Quartet use the soprano-alto-tenor-baritone (SATB) format of the classical saxophone quartet for jazz. In the 1990s, World Saxophone Quartet founder Hamiet Bluiett formed the quartet Baritone Nation (four baritones). The "jump swing" bands of the 1940s gave rise to rhythm and blues, featuring horn sections and exuberant, strong-toned, heavily rhythmic styles of saxophone playing with a melodic sense based on blues tonalities. Illinois Jacquet, Sam Butera, Arnett Cobb, and Jimmy Forrest were major influences on R&B tenor styles and Louis Jordan, Eddie "Cleanhead" Vinson, Earl Bostic, and Bull Moose Jackson were major influences on alto. The R&B saxophone players influenced later genres including rock and roll, ska, soul, and funk. Horn section work continued with Johnny Otis and Ray Charles featuring horn sections and the Memphis Horns, the Phenix Horns, and Tower of Power achieving distinction for their section playing. Horn sections were added to the Chicago and West Coast blues bands of Lowell Fulson, T-Bone Walker, B.B. King, and Guitar Slim. Rock and soul fusion bands such as Chicago, The Electric Flag, and Blood, Sweat, and Tears featured horn sections. Bobby Keys and Clarence Clemons became influential rock and roll saxophone stylists. Junior Walker, King Curtis and Maceo Parker became influential soul and funk saxophone stylists, influencing the more technical jazz-fusion sounds of Michael Brecker and Bob Mintzer and pop-jazz players such as Candy Dulfer. Unusual variants A number of experimental saxophones and saxophone-related instruments have appeared since Sax's original work, most with no lasting impact. During the early 1920s Reiffel &