Scatter Chart (Vega-Lite)

{
  "$schema": "https://vega.github.io/schema/vega-lite/v5.json",
  "title": "Scatter with Size and Shape",
  "width": 300,
  "height": 200,
  "data": {
    "values": [
      {"x": 1, "y": 28, "size": 100, "cat": "A"},
      {"x": 2, "y": 55, "size": 200, "cat": "B"},
      {"x": 3, "y": 43, "size": 150, "cat": "A"},
      {"x": 4, "y": 91, "size": 300, "cat": "B"},
      {"x": 5, "y": 81, "size": 120, "cat": "A"},
      {"x": 6, "y": 53, "size": 250, "cat": "B"}
    ]
  },
  "mark": "point",
  "encoding": {
    "x": {"field": "x", "type": "quantitative"},
    "y": {"field": "y", "type": "quantitative"},
    "size": {"field": "size", "type": "quantitative"},
    "shape": {"field": "cat", "type": "nominal"},
    "color": {"field": "cat", "type": "nominal"}
  }
}