# Structural Patterns > Every principle in this category is listed as a record. Page: Ontology · Principles Canonical: https://banes-lab.com/ontology#architecture-category-structural-patterns Listed in [Ontology · Principles](https://banes-lab.com/api/pages/ontology/principles.md), after [Creational Patterns](https://banes-lab.com/ontology/principles/architecture-category-creational-patterns.md) and before [Scalability / Performance / Optimization](https://banes-lab.com/ontology/principles/architecture-category-scalability-performance-optimization.md). Every principle in this category is listed as a record. Each record carries its kind, its severity, the scopes it applies at and the layer it lives in, then the edge relations that join it to other records, the records that point back at it, the contracts that answer to it and the tensions it takes part in. The descriptors say how it is violated, detected, measured, repaired and enforced. Where the record carries one, an exemplar shows the shape before and after the principle is applied. Relations diagram The relations inside this category. ```mermaid flowchart LR n_adapter_pattern["Adapter Pattern"] n_facade_pattern["Facade Pattern"] n_proxy_pattern["Proxy Pattern"] n_bridge_pattern["Bridge Pattern"] n_decorator_pattern["Decorator Pattern"] n_composite_pattern["Composite Pattern"] n_flyweight_pattern["Flyweight Pattern"] ``` ### Adapter Pattern - Kind: [pattern](https://banes-lab.com/records/kind/pattern.md) - Category: [Structural Patterns](https://banes-lab.com/ontology/principles/architecture-category-structural-patterns.md) - Severity: [mandatory](https://banes-lab.com/records/vocabulary/severity-mandatory.md) - Scope: integration, boundary - Layer: [Design Patterns Core](https://banes-lab.com/records/layer/design-patterns-core.md) Details Definition A design pattern that wraps a component with an incompatible interface so it implements the interface its callers expect. Requires [Incompatible Interfaces](https://banes-lab.com/records/lexicon/incompatible-interfaces.md) Reinforces [Anti-Corruption Layer](https://banes-lab.com/records/architecture/anti-corruption-layer.md), [Replaceability](https://banes-lab.com/records/architecture/replaceability.md) Enables [Interoperability](https://banes-lab.com/records/architecture/interoperability.md) In tension with [Mapping Overhead](https://banes-lab.com/records/lexicon/mapping-overhead.md) Conflicts with [Direct External Coupling](https://banes-lab.com/records/lexicon/direct-external-coupling.md) Referenced by [Interface-Based Design](https://banes-lab.com/records/architecture/interface-based-design.md) Tensions [Adapter Pattern / Mapping Overhead](https://banes-lab.com/records/tension/adapter-pattern-mapping-overhead.md) Distinct from [Anti-Corruption Layer](https://banes-lab.com/records/architecture/anti-corruption-layer.md): An adapter fits one incompatible interface to the one expected, while an anti-corruption layer translates a whole external model into the local domain's terms. Violated by foreign model leaking into core Detected by external SDK types in domain/application Measured by external leakage count Refactored by Add Adapter, Add Translator Enforced by boundary import rules Before ```typescript function saveFoo(foo: Foo) { return legacyClient.put(foo.id, foo.name, foo.count); } ``` After ```typescript class LegacyFooAdapter implements FooStore { constructor(private readonly client: LegacyClient) {} save(foo: Foo) { return this.client.put(foo.id, foo.name, foo.count); } } ``` How it is checked Checked by boundary import rules Population Every boundary, wrapper and composite structure that sits between a caller and the objects it uses Freshness A verdict stands until the wrapped interface or its callers change Refusal The boundary import rule or the conformance test fails a caller that reaches past the structure Observation Imports and call sites that cross the structure, read from source Evidence None, because the catalog states this check as a class, so a watched run belongs to each system that adopts it Authoritative side The structure's interface, which every caller goes through Depends on [Incompatible Interfaces](https://banes-lab.com/records/lexicon/incompatible-interfaces.md), [Anti-Corruption Layer](https://banes-lab.com/records/architecture/anti-corruption-layer.md), [Replaceability](https://banes-lab.com/records/architecture/replaceability.md), [Interoperability](https://banes-lab.com/records/architecture/interoperability.md) Shape it refuses [Direct External Coupling](https://banes-lab.com/records/lexicon/direct-external-coupling.md) ### Facade Pattern - Kind: [pattern](https://banes-lab.com/records/kind/pattern.md) - Category: [Structural Patterns](https://banes-lab.com/ontology/principles/architecture-category-structural-patterns.md) - Severity: [recommended](https://banes-lab.com/records/vocabulary/severity-recommended.md) - Scope: module, subsystem, API - Layer: [Design Patterns Core](https://banes-lab.com/records/layer/design-patterns-core.md) Details Definition A design pattern that gives a subsystem one simple entry point, so callers do not depend on its parts. Requires [Subsystem Complexity](https://banes-lab.com/records/lexicon/subsystem-complexity.md) Reinforces [Encapsulation](https://banes-lab.com/records/architecture/encapsulation.md), [Information Hiding](https://banes-lab.com/records/architecture/information-hiding.md) Enables [Simplified Access](https://banes-lab.com/records/lexicon/simplified-access.md) In tension with [Over-Centralization](https://banes-lab.com/records/lexicon/over-centralization.md) Conflicts with [Leaky Subsystem API](https://banes-lab.com/records/lexicon/leaky-subsystem-api.md) Tensions [Facade Pattern / Over-Centralization](https://banes-lab.com/records/tension/facade-pattern-over-centralization.md) Violated by consumers depending on many subsystem internals Detected by broad dependency surface to subsystem Measured by consumer dependency count Refactored by Introduce Facade Enforced by API boundary rules Before ```typescript const foo = fooValidator.validate(fooParser.parse(raw)); await fooStore.save(foo); await fooEvents.publish(foo); ``` After ```typescript class FooFacade { async create(raw: string) { const foo = fooValidator.validate(fooParser.parse(raw)); await fooStore.save(foo); await fooEvents.publish(foo); } } ``` How it is checked Checked by API boundary rules Population Every boundary, wrapper and composite structure that sits between a caller and the objects it uses Freshness A verdict stands until the wrapped interface or its callers change Refusal The boundary import rule or the conformance test fails a caller that reaches past the structure Observation Imports and call sites that cross the structure, read from source Evidence None, because the catalog states this check as a class, so a watched run belongs to each system that adopts it Authoritative side The structure's interface, which every caller goes through Depends on [Subsystem Complexity](https://banes-lab.com/records/lexicon/subsystem-complexity.md), [Encapsulation](https://banes-lab.com/records/architecture/encapsulation.md), [Information Hiding](https://banes-lab.com/records/architecture/information-hiding.md), [Simplified Access](https://banes-lab.com/records/lexicon/simplified-access.md) Shape it refuses [Leaky Subsystem API](https://banes-lab.com/records/lexicon/leaky-subsystem-api.md) ### Proxy Pattern - Kind: [pattern](https://banes-lab.com/records/kind/pattern.md) - Category: [Structural Patterns](https://banes-lab.com/ontology/principles/architecture-category-structural-patterns.md) - Severity: [contextual](https://banes-lab.com/records/vocabulary/severity-contextual.md) - Scope: access control, remote access, lazy loading - Layer: [Design Patterns Core](https://banes-lab.com/records/layer/design-patterns-core.md) Details Definition A design pattern that places a stand-in with the same interface in front of an object, to control, defer or cache access to it. Requires [Controlled Access](https://banes-lab.com/records/lexicon/controlled-access.md) Reinforces [Encapsulation](https://banes-lab.com/records/architecture/encapsulation.md), [Security](https://banes-lab.com/records/lexicon/security.md) Enables [Lazy Load](https://banes-lab.com/records/lexicon/lazy-load.md), [Authorization](https://banes-lab.com/records/architecture/authorization.md), [Remote Stub](https://banes-lab.com/records/lexicon/remote-stub.md) In tension with [Transparency / Debugging](https://banes-lab.com/records/lexicon/transparency-debugging.md) Conflicts with [Direct Access](https://banes-lab.com/records/lexicon/direct-access.md) Tensions [Proxy Pattern / Transparency / Debugging](https://banes-lab.com/records/tension/proxy-pattern-transparency-debugging.md) Violated by uncontrolled direct resource access Detected by bypassed access wrapper Measured by proxy bypass count Refactored by Introduce Proxy Enforced by access rules Before ```typescript function loadFoo(id: FooId) { return remoteFooStore.find(id); } ``` After ```typescript class CachingFooStoreProxy implements FooStore { constructor(private readonly target: FooStore) {} async find(id: FooId) { const cached = fooCache.get(id); if (cached) return cached; const foo = await this.target.find(id); fooCache.set(id, foo); return foo; } } ``` How it is checked Checked by access rules Population Every boundary, wrapper and composite structure that sits between a caller and the objects it uses Freshness A verdict stands until the wrapped interface or its callers change Refusal The boundary import rule or the conformance test fails a caller that reaches past the structure Observation Imports and call sites that cross the structure, read from source Evidence None, because the catalog states this check as a class, so a watched run belongs to each system that adopts it Authoritative side The structure's interface, which every caller goes through Depends on [Controlled Access](https://banes-lab.com/records/lexicon/controlled-access.md), [Encapsulation](https://banes-lab.com/records/architecture/encapsulation.md), [Security](https://banes-lab.com/records/lexicon/security.md), [Lazy Load](https://banes-lab.com/records/lexicon/lazy-load.md), [Authorization](https://banes-lab.com/records/architecture/authorization.md), [Remote Stub](https://banes-lab.com/records/lexicon/remote-stub.md) Shape it refuses [Direct Access](https://banes-lab.com/records/lexicon/direct-access.md) ### Bridge Pattern - Kind: [pattern](https://banes-lab.com/records/kind/pattern.md) - Category: [Structural Patterns](https://banes-lab.com/ontology/principles/architecture-category-structural-patterns.md) - Severity: [contextual](https://banes-lab.com/records/vocabulary/severity-contextual.md) - Scope: abstraction, implementation variation - Layer: [Design Patterns Core](https://banes-lab.com/records/layer/design-patterns-core.md) Details Definition A design pattern that separates two independent axes of variation into two hierarchies joined by composition. Requires [Independent Variation Axes](https://banes-lab.com/records/lexicon/independent-variation-axes.md) Reinforces [Composition Over Inheritance](https://banes-lab.com/records/architecture/composition-over-inheritance.md) Enables [Implementation Swap](https://banes-lab.com/records/lexicon/implementation-swap.md) In tension with [Indirection](https://banes-lab.com/records/lexicon/indirection.md) Conflicts with [Cartesian Inheritance Explosion](https://banes-lab.com/records/lexicon/cartesian-inheritance-explosion.md) Tensions [Bridge Pattern / Indirection](https://banes-lab.com/records/tension/bridge-pattern-indirection.md) Violated by subclass explosion for combinations Detected by parallel hierarchies / deep variant classes Measured by variant class count Refactored by Introduce Bridge Enforced by [design review](https://banes-lab.com/records/architecture/design-review.md) Before ```typescript class SqlJsonFooExporter {} class SqlCsvFooExporter {} class MemoryJsonFooExporter {} class MemoryCsvFooExporter {} ``` After ```typescript interface FooSource { read(): Promise; } interface FooFormat { encode(foos: readonly Foo[]): string; } class FooExporter { constructor(private readonly source: FooSource, private readonly format: FooFormat) {} async export() { return this.format.encode(await this.source.read()); } } ``` How it is checked Checked by design review Population Every boundary, wrapper and composite structure that sits between a caller and the objects it uses Freshness A verdict stands until the wrapped interface or its callers change Refusal The boundary import rule or the conformance test fails a caller that reaches past the structure Observation Imports and call sites that cross the structure, read from source Evidence None, because the catalog states this check as a class, so a watched run belongs to each system that adopts it Authoritative side The structure's interface, which every caller goes through Depends on [Independent Variation Axes](https://banes-lab.com/records/lexicon/independent-variation-axes.md), [Composition Over Inheritance](https://banes-lab.com/records/architecture/composition-over-inheritance.md), [Implementation Swap](https://banes-lab.com/records/lexicon/implementation-swap.md) Shape it refuses [Cartesian Inheritance Explosion](https://banes-lab.com/records/lexicon/cartesian-inheritance-explosion.md) ### Decorator Pattern - Kind: [pattern](https://banes-lab.com/records/kind/pattern.md) - Category: [Structural Patterns](https://banes-lab.com/ontology/principles/architecture-category-structural-patterns.md) - Severity: [contextual](https://banes-lab.com/records/vocabulary/severity-contextual.md) - Scope: behavior composition - Layer: [Design Patterns Core](https://banes-lab.com/records/layer/design-patterns-core.md) Details Definition A design pattern that adds behavior to an object by wrapping it in another object with the same interface. Requires [Common Interface](https://banes-lab.com/records/lexicon/common-interface.md) Reinforces [Open/Closed Principle (OCP)](https://banes-lab.com/records/architecture/open-closed.md), [Composability](https://banes-lab.com/records/architecture/composability.md) Enables [Runtime Behavior Extension](https://banes-lab.com/records/lexicon/runtime-behavior-extension.md) In tension with [Stack Debugging](https://banes-lab.com/records/lexicon/stack-debugging.md) Conflicts with [Subclass Explosion](https://banes-lab.com/records/lexicon/subclass-explosion.md) Referenced by [Composition Over Inheritance](https://banes-lab.com/records/architecture/composition-over-inheritance.md) Tensions [Decorator Pattern / Stack Debugging](https://banes-lab.com/records/tension/decorator-pattern-stack-debugging.md) Violated by many subclasses for optional features Detected by repeated wrapper-like subclasses Measured by variant explosion count Refactored by Introduce Decorator Enforced by interface conformance tests Before ```typescript class LoggedSqlFooStore extends SqlFooStore { override save(foo: Foo) { logger.info("foo.saved", { fooId: foo.id }); return super.save(foo); } } ``` After ```typescript class LoggedFooStore implements FooStore { constructor(private readonly inner: FooStore, private readonly log: Log) {} save(foo: Foo) { this.log.write(foo.id); return this.inner.save(foo); } } ``` How it is checked Checked by interface conformance tests Population Every boundary, wrapper and composite structure that sits between a caller and the objects it uses Freshness A verdict stands until the wrapped interface or its callers change Refusal The boundary import rule or the conformance test fails a caller that reaches past the structure Observation Imports and call sites that cross the structure, read from source Evidence None, because the catalog states this check as a class, so a watched run belongs to each system that adopts it Authoritative side The structure's interface, which every caller goes through Depends on [Common Interface](https://banes-lab.com/records/lexicon/common-interface.md), [Open/Closed Principle (OCP)](https://banes-lab.com/records/architecture/open-closed.md), [Composability](https://banes-lab.com/records/architecture/composability.md), [Runtime Behavior Extension](https://banes-lab.com/records/lexicon/runtime-behavior-extension.md) Shape it refuses [Subclass Explosion](https://banes-lab.com/records/lexicon/subclass-explosion.md) ### Composite Pattern - Kind: [pattern](https://banes-lab.com/records/kind/pattern.md) - Category: [Structural Patterns](https://banes-lab.com/ontology/principles/architecture-category-structural-patterns.md) - Severity: [recommended](https://banes-lab.com/records/vocabulary/severity-recommended.md) - Scope: structure, tree, hierarchy - Layer: [Design Patterns Core](https://banes-lab.com/records/layer/design-patterns-core.md) Details Definition A design pattern that gives leaves and groups one interface, so a tree is traversed without checking which kind each node is. Requires [Uniform Component Interface](https://banes-lab.com/records/lexicon/uniform-component-interface.md) Reinforces [Uniform Interface](https://banes-lab.com/records/architecture/uniform-interface.md), [Open/Closed Principle (OCP)](https://banes-lab.com/records/architecture/open-closed.md) Enables [Recursive Composition](https://banes-lab.com/records/lexicon/recursive-composition.md), [Leaf/Composite Transparency](https://banes-lab.com/records/lexicon/leaf-composite-transparency.md) In tension with [Type Safety](https://banes-lab.com/records/architecture/type-safety.md) Conflicts with [Leaf-vs-Container Special-Casing](https://banes-lab.com/records/lexicon/leaf-vs-container-special-casing.md) Tensions [Composite Pattern / Type Safety](https://banes-lab.com/records/tension/composite-pattern-type-safety.md) Violated by callers branching on leaf-vs-container at every node Detected by isContainer/isLeaf conditionals during traversal Measured by node-kind conditional count Refactored by Unify Leaf and Composite behind one interface Enforced by [design review](https://banes-lab.com/records/architecture/design-review.md) Before ```typescript function totalFoo(item: Foo | FooGroup): number { if ("children" in item) return item.children.reduce((sum, child) => sum + totalFoo(child), 0); return item.value; } ``` After ```typescript interface FooComponent { total(): number; } class FooLeaf implements FooComponent { constructor(private readonly value: number) {} total() { return this.value; } } class FooGroup implements FooComponent { constructor(private readonly children: readonly FooComponent[]) {} total() { return this.children.reduce((sum, child) => sum + child.total(), 0); } } ``` How it is checked Checked by design review Population Every boundary, wrapper and composite structure that sits between a caller and the objects it uses Freshness A verdict stands until the wrapped interface or its callers change Refusal The boundary import rule or the conformance test fails a caller that reaches past the structure Observation Imports and call sites that cross the structure, read from source Evidence None, because the catalog states this check as a class, so a watched run belongs to each system that adopts it Authoritative side The structure's interface, which every caller goes through Depends on [Uniform Component Interface](https://banes-lab.com/records/lexicon/uniform-component-interface.md), [Uniform Interface](https://banes-lab.com/records/architecture/uniform-interface.md), [Open/Closed Principle (OCP)](https://banes-lab.com/records/architecture/open-closed.md), [Recursive Composition](https://banes-lab.com/records/lexicon/recursive-composition.md), [Leaf/Composite Transparency](https://banes-lab.com/records/lexicon/leaf-composite-transparency.md) Shape it refuses [Leaf-vs-Container Special-Casing](https://banes-lab.com/records/lexicon/leaf-vs-container-special-casing.md) ### Flyweight Pattern - Kind: [pattern](https://banes-lab.com/records/kind/pattern.md) - Category: [Structural Patterns](https://banes-lab.com/ontology/principles/architecture-category-structural-patterns.md) - Severity: [contextual](https://banes-lab.com/records/vocabulary/severity-contextual.md) - Scope: structure, memory, sharing - Layer: [Design Patterns Core](https://banes-lab.com/records/layer/design-patterns-core.md) Details Definition A design pattern that shares one copy of immutable intrinsic state among many objects, each keeping only its own extrinsic state. Requires [Separable Intrinsic State](https://banes-lab.com/records/lexicon/separable-intrinsic-state.md) Reinforces [Memory Efficiency](https://banes-lab.com/records/architecture/memory-efficiency.md) Enables [Shared Immutable State](https://banes-lab.com/records/lexicon/shared-immutable-state.md), [High-Cardinality Object Reuse](https://banes-lab.com/records/lexicon/high-cardinality-object-reuse.md) In tension with [Complexity](https://banes-lab.com/records/lexicon/complexity.md) Conflicts with [Per-Instance Duplicate State](https://banes-lab.com/records/lexicon/per-instance-duplicate-state.md) Tensions [Flyweight Pattern / Complexity](https://banes-lab.com/records/tension/complexity-flyweight-pattern.md) Violated by identical heavy state duplicated across many instances Detected by repeated equal intrinsic state across objects Measured by duplicate-state memory footprint Refactored by Extract Flyweight, Share Intrinsic State Enforced by profiling review Before ```typescript const icons = foos.map(foo => new FooIcon(foo.position, loadSprite(foo.kind))); ``` After ```typescript const spriteCache = new Map(); function fooSprite(kind: string) { const cached = spriteCache.get(kind); if (cached) return cached; const sprite = loadSprite(kind); spriteCache.set(kind, sprite); return sprite; } const icons = foos.map(foo => ({ position: foo.position, sprite: fooSprite(foo.kind) })); ``` How it is checked Checked by profiling review Population Every boundary, wrapper and composite structure that sits between a caller and the objects it uses Freshness A verdict stands until the wrapped interface or its callers change Refusal The boundary import rule or the conformance test fails a caller that reaches past the structure Observation Imports and call sites that cross the structure, read from source Evidence None, because the catalog states this check as a class, so a watched run belongs to each system that adopts it Authoritative side The structure's interface, which every caller goes through Depends on [Separable Intrinsic State](https://banes-lab.com/records/lexicon/separable-intrinsic-state.md), [Memory Efficiency](https://banes-lab.com/records/architecture/memory-efficiency.md), [Shared Immutable State](https://banes-lab.com/records/lexicon/shared-immutable-state.md), [High-Cardinality Object Reuse](https://banes-lab.com/records/lexicon/high-cardinality-object-reuse.md) Shape it refuses [Per-Instance Duplicate State](https://banes-lab.com/records/lexicon/per-instance-duplicate-state.md) ## Links to - [pattern](https://banes-lab.com/records/kind/pattern.md) - [mandatory](https://banes-lab.com/records/vocabulary/severity-mandatory.md) - [Design Patterns Core](https://banes-lab.com/records/layer/design-patterns-core.md) - [Incompatible Interfaces](https://banes-lab.com/records/lexicon/incompatible-interfaces.md) - [Anti-Corruption Layer](https://banes-lab.com/records/architecture/anti-corruption-layer.md) - [Replaceability](https://banes-lab.com/records/architecture/replaceability.md) - [Interoperability](https://banes-lab.com/records/architecture/interoperability.md) - [Mapping Overhead](https://banes-lab.com/records/lexicon/mapping-overhead.md) - [Direct External Coupling](https://banes-lab.com/records/lexicon/direct-external-coupling.md) - [Interface-Based Design](https://banes-lab.com/records/architecture/interface-based-design.md) - [Adapter Pattern / Mapping Overhead](https://banes-lab.com/records/tension/adapter-pattern-mapping-overhead.md) - [recommended](https://banes-lab.com/records/vocabulary/severity-recommended.md) - [Subsystem Complexity](https://banes-lab.com/records/lexicon/subsystem-complexity.md) - [Encapsulation](https://banes-lab.com/records/architecture/encapsulation.md) - [Information Hiding](https://banes-lab.com/records/architecture/information-hiding.md) - [Simplified Access](https://banes-lab.com/records/lexicon/simplified-access.md) - [Over-Centralization](https://banes-lab.com/records/lexicon/over-centralization.md) - [Leaky Subsystem API](https://banes-lab.com/records/lexicon/leaky-subsystem-api.md) - [Facade Pattern / Over-Centralization](https://banes-lab.com/records/tension/facade-pattern-over-centralization.md) - [contextual](https://banes-lab.com/records/vocabulary/severity-contextual.md) - [Controlled Access](https://banes-lab.com/records/lexicon/controlled-access.md) - [Security](https://banes-lab.com/records/lexicon/security.md) - [Lazy Load](https://banes-lab.com/records/lexicon/lazy-load.md) - [Authorization](https://banes-lab.com/records/architecture/authorization.md) - [Remote Stub](https://banes-lab.com/records/lexicon/remote-stub.md) - [Transparency / Debugging](https://banes-lab.com/records/lexicon/transparency-debugging.md) - [Direct Access](https://banes-lab.com/records/lexicon/direct-access.md) - [Proxy Pattern / Transparency / Debugging](https://banes-lab.com/records/tension/proxy-pattern-transparency-debugging.md) - [Independent Variation Axes](https://banes-lab.com/records/lexicon/independent-variation-axes.md) - [Composition Over Inheritance](https://banes-lab.com/records/architecture/composition-over-inheritance.md) - [Implementation Swap](https://banes-lab.com/records/lexicon/implementation-swap.md) - [Indirection](https://banes-lab.com/records/lexicon/indirection.md) - [Cartesian Inheritance Explosion](https://banes-lab.com/records/lexicon/cartesian-inheritance-explosion.md) - [Bridge Pattern / Indirection](https://banes-lab.com/records/tension/bridge-pattern-indirection.md) - [Design Review](https://banes-lab.com/records/architecture/design-review.md) - [Common Interface](https://banes-lab.com/records/lexicon/common-interface.md) - [Open/Closed Principle](https://banes-lab.com/records/architecture/open-closed.md) - [Composability](https://banes-lab.com/records/architecture/composability.md) - [Runtime Behavior Extension](https://banes-lab.com/records/lexicon/runtime-behavior-extension.md) - [Stack Debugging](https://banes-lab.com/records/lexicon/stack-debugging.md) - [Subclass Explosion](https://banes-lab.com/records/lexicon/subclass-explosion.md) - [Decorator Pattern / Stack Debugging](https://banes-lab.com/records/tension/decorator-pattern-stack-debugging.md) - [Uniform Component Interface](https://banes-lab.com/records/lexicon/uniform-component-interface.md) - [Uniform Interface](https://banes-lab.com/records/architecture/uniform-interface.md) - [Recursive Composition](https://banes-lab.com/records/lexicon/recursive-composition.md) - [Leaf/Composite Transparency](https://banes-lab.com/records/lexicon/leaf-composite-transparency.md) - [Type Safety](https://banes-lab.com/records/architecture/type-safety.md) - [Leaf-vs-Container Special-Casing](https://banes-lab.com/records/lexicon/leaf-vs-container-special-casing.md) - [Composite Pattern / Type Safety](https://banes-lab.com/records/tension/composite-pattern-type-safety.md) - [Separable Intrinsic State](https://banes-lab.com/records/lexicon/separable-intrinsic-state.md) - [Memory Efficiency](https://banes-lab.com/records/architecture/memory-efficiency.md) - [Shared Immutable State](https://banes-lab.com/records/lexicon/shared-immutable-state.md) - [High-Cardinality Object Reuse](https://banes-lab.com/records/lexicon/high-cardinality-object-reuse.md) - [Complexity](https://banes-lab.com/records/lexicon/complexity.md) - [Per-Instance Duplicate State](https://banes-lab.com/records/lexicon/per-instance-duplicate-state.md) - [Flyweight Pattern / Complexity](https://banes-lab.com/records/tension/complexity-flyweight-pattern.md) ## Linked from - [The layer topology](https://banes-lab.com/ontology/schema/the-layer-topology.md) - [The membership](https://banes-lab.com/ontology/schema/the-membership.md)