{
  "$schema": "urn:prism:schema:v1:spec",
  "title": "Shared y-scale domain union",
  "resolve": {"scale": {"y": "shared"}},
  "layer": [
    {
      "$schema": "urn:prism:schema:v1:spec",
      "data": {"values": [
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        {"x": "c", "y": 25},
        {"x": "d", "y": 50}
      ]},
      "mark": "bar",
      "encoding": {
        "x": {"field": "x", "type": "nominal"},
        "y": {"field": "y", "type": "quantitative"}
      }
    },
    {
      "$schema": "urn:prism:schema:v1:spec",
      "data": {"values": [
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        {"x": "b", "y": 60},
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      "mark": {"type": "rule", "stroke": "#dc2626", "stroke_dash": [4, 2]},
      "encoding": {
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}