{
  "$schema": "urn:prism:schema:v1:spec",
  "data": {"name": "d", "values": [
    {"t": "2026-01-01", "y": 1.0},
    {"t": "2026-04-01", "y": 5.0},
    {"t": "2026-07-01", "y": 10.0}
  ]},
  "mark": "line",
  "encoding": {
    "x": {"field": "t", "type": "temporal", "scale": {"type": "time"}},
    "y": {"field": "y", "type": "quantitative"}
  }
}