{
  "params": {
    "rows": {
      "type": "range",
      "min": 6,
      "max": 24,
      "step": 1,
      "default": 16,
      "label": "Seat rows",
      "describe": "Number of seat rows. Every 8 rows a walkway with a low wall starts a new tier. 24 rows rise about 14 m; the outer arcade grows a storey for every ~4.5 m."
    },
    "span": {
      "type": "range",
      "min": 15,
      "max": 45,
      "step": 5,
      "default": 30,
      "label": "Span",
      "describe": "Angle of the wedge in degrees. 360 / span copies close the ring: 30 degrees needs 12 pieces, 45 needs 8."
    },
    "arcade": {
      "type": "toggle",
      "default": true,
      "label": "Outer arcade",
      "describe": "The tall outer wall of stacked arches behind the top row, like the Colosseum. Off leaves an open hillside-style theatre edge."
    },
    "stone": {
      "type": "choice",
      "options": [
        "travertine",
        "sandstone",
        "marble",
        "grey"
      ],
      "default": "travertine",
      "label": "Stone",
      "describe": "travertine (warm cream, Rome), sandstone (golden, North Africa and Anatolia), marble (white) or grey (weathered limestone)."
    },
    "ruin": {
      "type": "range",
      "min": 0,
      "max": 1,
      "step": 0.05,
      "default": 0,
      "label": "Ruin",
      "describe": "0 is complete. Higher values pull seat stones out of the upper rows, knock storeys off the outer arcade and scatter blocks. Adjacent pieces use different damage, so a ruined ring never repeats exactly."
    }
  },
  "presets": {
    "colosseum wedge": {
      "rows": 24,
      "span": 30,
      "arcade": true,
      "stone": "travertine"
    },
    "provincial arena ruin": {
      "rows": 14,
      "span": 30,
      "arcade": true,
      "stone": "sandstone",
      "ruin": 0.55
    },
    "hillside theatre": {
      "rows": 12,
      "span": 45,
      "arcade": false,
      "stone": "marble",
      "ruin": 0.2
    }
  },
  "night": null
}