Wall of Sound but Phil came along and took these to make sounds that had not been used in the past. I thought it was ingenious." During the mid-1950s, Spector worked with Brill Building songwriters Jerry Leiber and Mike Stoller during a period where they sought a fuller sound by the use of excessive instrumentation, using up to five electric guitars and four percussionists. This was later to evolve into Spector's Wall of Sound, which Leiber and Stoller consider to be very distinct from what they were doing, stating: "Phil was the first one to use multiple drum kits, three pianos and so
Axiom of pairing then produces the desired result, {"A","A","A"}. We can extend this schema to include "n"=0 if we interpret that case as the axiom of empty set. Thus, one may use this as an axiom schema in the place of the axioms of empty set and pairing. Normally, however, one uses the axioms of empty set and pairing separately, and then proves this as a theorem schema. Note that adopting this as an axiom schema will not replace the axiom of union, which is still needed for other situations. Another axiom which implies the axiom of pairing in the presence of the