Sample graph data for ladder visualization

graph.json

{
  "nodes": [
    {"player": "Andy", "rating": 1640},
    {"player": "Bob", "rating": 1570},
    {"player": "Carmen", "rating": 1590}
  ],

  "edges": [
    {"p1": "Bob", "p2": "Andy", "difference": 50},
    {"p1": "Carmen", "p2": "Bob", "difference": 20},
    {"p1": "Andy", "p2": "Carmen", "difference": 10}
  ]
}