**What was implemented**  
- Added two concrete node classes – `ReflectionNode` and `RewritingNode` – in `src/nodes.js`.  
- Updated the public API in `src/index.js` to export the new classes.  
- Wrote a comprehensive test suite (`tests/graph.test.js`) that checks:  
  1. Nodes of all three types can be added.  
  2. Duplicate IDs are rejected.  
  3. Edges can be created between any node types.  
  4. Removing a node cleans up its edges.  
  5. Traversal works on disconnected sub‑graphs.

**Why the main parts satisfy the requirements**  
- The new node classes inherit from `Node`, so the existing `Graph.addNode` logic (`instanceof Node`) automatically accepts them.  
- Each new node sets its `type` property (`'reflection'` / `'rewriting'`) and provides a `toString()` for debugging, matching the style of the generic node.  
- Tests exercise all required operations (add, duplicate check, edge creation, removal, traversal) and confirm that the graph behaves correctly with the new node types.

**Key code excerpts**

*src/nodes.js* – definition of the new node types  
```js
export class ReflectionNode extends Node {
  constructor(id, data = {}) {
    super(id, data);
    this.type = 'reflection';
  }
  toString() { return `ReflectionNode(${this.id})`; }
}

export class RewritingNode extends Node {
  constructor(id, data = {}) {
    super(id, data);
    this.type = 'rewriting';
  }
  toString() { return `RewritingNode(${this.id})`; }
}
```

*tests/graph.test.js* – adding nodes and verifying presence  
```js
const n1 = new Node('n1');
const r1 = new ReflectionNode('r1');
const w1 = new RewritingNode('w1');

graph.addNode(n1);
graph.addNode(r1);
graph.addNode(w1);

expect(graph.getNode('n1')).toBe(n1);
expect(graph.getNode('r1')).toBe(r1);
expect(graph.getNode('w1')).toBe(w1);
```

*src/graph.js* – node type check (unchanged, but still relevant)  
```js
addNode(node) {
  if (!(node instanceof Node)) {
    throw new Error('Only Node instances can be added');
  }
  ...
}
```

**Honest limitations**  
- The new node types currently only differ by their `type` field and `toString()` method; no additional behavior (e.g., special traversal rules) is implemented.  
- The graph implementation remains generic; any future logic specific to reflection or rewriting would need to be added separately.