In the 1950s some composers became frustrated with conventional musical notation. It didn’t allow them to communicate to performers the sorts of sounds they wanted them to make. As a result, some developed various forms of alternative notation, which used shapes or patterns in addition to, or instead of, existing notation. Morton Feldman’s Projection (1950-1) for various acoustic instruments was an early example, and used horizontal rows of connected boxes to instruct the performers. Other composers who made use of graphic notation in the 1960s and 70s include Penderecki—who in exploring new timbres and textures sometimes required new forms of notation—Netty Simons, and Luna Alcalay.