graph TD
            A[Автобус] --- B[Водитель]
            A --- C[Остановка]
            A --- D[Пассажир]
            D --- E[Билет]
            E --- F[Контролер]
            D --- C
            style A fill:#f9f,stroke:#333,stroke-width:2px
            style B fill:#bbf,stroke:#333,stroke-width:2px
            style C fill:#dfd,stroke:#333,stroke-width:2px
            style D fill:#fdd,stroke:#333,stroke-width:2px
            style E fill:#ddf,stroke:#333,stroke-width:2px
            style F fill:#ffd,stroke:#333,stroke-width:2px