Status: IN
Builder-Visitor's bidirectional functional duality (Builder analyzing without creating, Visitor creating during traversal) validates the same kind of classification permeability demonstrated by cross-category pattern migration — construction and computation, like Creational-Structural-Behavioral, are useful pedagogical categories but architecturally permeable boundaries.
Builder-Visitor's role-reversal parallels Composite-Singleton's category migration — both demonstrate classification permeability at different levels
Depends on (SL): builder-visitor-bidirectional-functional-duality, cross-category-pattern-migration-validates-classification-permeability