{
  "id": "root",
  "layoutOptions": {
    "elk.algorithm": "layered"
  },
  "children": [
    {"id": "n1", "width": 30, "height": 30},
    {"id": "n2", "width": 30, "height": 30},
    {"id": "n3", "width": 30, "height": 30}
  ],
  "edges": [
    {"id": "e1", "sources": ["n1"], "targets": ["n2"]},
    {"id": "e2", "sources": ["n1"], "targets": ["n3"]}
  ]
}