Graph

```mermaid graph TD;

A B

A → B B → A

classDef red fill:#FF0000,stroke:#000,color:#fff; classDef green fill:#008000,stroke:#000,color:#fff; classDef blue fill:#0000FF,stroke:#fff,color:#fff; classDef yellow fill:#FFFF00,stroke:#000,color:#000; classDef violet fill:#8A2BE2,stroke:#000,color:#fff; classDef gray fill:#808080,stroke:#000,color:#fff; classDef orange fill:#FFA500,stroke:#000,color:#fff; class A red class B green ```