Status: IN
The Decorator pattern occupies a distinct compositional niche differentiated along two axes: from Adapter by preserving interface while changing responsibilities (not converting interfaces), and from Composite by adding responsibilities to individual objects rather than modeling part-whole hierarchies — positioning Decorator uniquely as the single-object responsibility-augmentation pattern.
Depth-1 — triangulating Decorator's position from two differentiation axes (vs Adapter and vs Composite) identifies its unique niche in a way neither comparison alone does
Depends on (SL): decorator-vs-adapter-responsibilities-not-interface, composite-vs-decorator-different-intents