tools/json-graph/tree2.json

{
  "graph": {
    "version": "1.0",
    "type": "tree",
    "directed": true,
    "root": 0,
    "nodes": [
      { "id": 0, "label": "Top",    "edges": [ 1, 2 ] },
      { "id": 1, "label": "Child1" },
      { "id": 2, "label": "Child2", "edges": [ 3 ] },
      { "id": 3, "label": "Grandchild" }
    ]
  }
}