Status: IN
Complete pattern application judgment requires mastery of two distinct constraint types: inter-pattern tradeoffs (choosing between competing patterns like Observer vs. Mediator based on reusability vs. simplicity) and intra-pattern prerequisites (recognizing when a pattern's own structural assumptions are unmet, as Visitor requires stable element hierarchies) — neither alone suffices.
Visitor demonstrates intra-pattern constraints (stable structure required) while Observer-Mediator demonstrates inter-pattern tradeoffs
Depends on (SL): visitor-exposes-pattern-mutual-constraints, observer-mediator-distribution-centralization-tradeoff