{
  "$schema": "urn:prism:schema:v1:spec",
  "title": "Region share (donut)",
  "data": {
    "name": "shares",
    "values": [
      {"region": "NA", "value": 42},
      {"region": "EU", "value": 31},
      {"region": "APAC", "value": 27}
    ]
  },
  "mark": {"type": "donut", "inner_radius": 40, "outer_radius": 80},
  "encoding": {
    "theta": {"field": "value",  "type": "quantitative"},
    "color": {"field": "region", "type": "nominal"}
  }
}