{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "$id": "https://cdn.jsdelivr.net/npm/@pie-element/venn-classification@0.1.7/dist/schemas/session.schema.json",
  "type": "object",
  "properties": {
    "id": {
      "type": "string",
      "description": "Identifier of the session"
    },
    "element": {
      "type": "string",
      "description": "The element the session belongs to"
    },
    "placements": {
      "type": "object",
      "additionalProperties": {
        "anyOf": [
          {
            "$ref": "#/definitions/Region"
          },
          {
            "type": "null"
          }
        ]
      },
      "description": "Keyed by tile id; `null` = still in tray, `[]` = outside region."
    },
    "completed": {
      "type": "boolean"
    }
  },
  "definitions": {
    "Region": {
      "type": "array",
      "items": {
        "type": "number"
      }
    }
  }
}