graph LR
    subgraph "Beginner Friendly"
        A1[Singleton]
        A2[Factory]
        A3[Facade]
    end
    
    subgraph "Intermediate"
        B1[Builder]
        B2[Adapter]
        B3[Strategy]
        B4[Observer]
    end
    
    subgraph "Advanced"
        C1[Decorator]
        C2[Command]
    end
    
    A1 --> B1
    A2 --> B2
    A3 --> B3
    B1 --> C1
    B2 --> C1
    B3 --> C2
    B4 --> C2