Status: OUT
The GoF's three-tier progressive validation (MVC→Lexi→ET++ demonstrating pattern composition at increasing scope) reliably establishes pattern composition as a design methodology — but only within the catalog's deliberate scope boundaries (excluding concurrency, distribution, domain-specific patterns) and within its language-epoch validity (C++/Smalltalk feature set determining pattern necessity).
Progressive validation's reliability is bounded by both the catalog's explicit scope exclusions and the language-relativity of pattern necessity
Depends on (SL): progressive-validation-three-tier-pattern-composition, catalog-completeness-within-deliberate-bounds