The Pitch-class set theory and its extensions constitute an important basis for mastering multi- layered atonal composition. The SuperCollider environment offers significant possibilities of applying this technique in the creation of abstract Pitch-class designs that may be used as a part of more complex algorithmic composition developments. This paper presents pcslib-sc a quark (library) for Pitch-class set design in SuperCollider and an use case in order to demonstrate its musical relevance.