{
  "$schema": "urn:prism:schema:v1:spec",
  "title": "Pinned gridlines",
  "data": {"name": "d", "values": [
    {"quarter": "Q1", "revenue": 18.4},
    {"quarter": "Q2", "revenue": 31.7},
    {"quarter": "Q3", "revenue": 44.2},
    {"quarter": "Q4", "revenue": 62.9}
  ]},
  "mark": "bar",
  "encoding": {
    "x": {"field": "quarter", "type": "nominal", "axis": {"grid": false}},
    "y": {
      "field": "revenue",
      "type": "quantitative",
      "scale": {"domain": [0, 80]},
      "axis": {"values": [0, 25, 50, 75], "title": "Revenue ($M)"}
    }
  }
}