{
  "version": "1.0",
  "coordinate system":{"model":"cartesian"},
  "features":
  [
    {
       "model":"oceanic plate", "name":"Overriding Plate", "max depth":100e3, 
       "coordinates":[[0,0],[0,1000e3],[1500e3,1000e3],[1600e3,350e3],[1500e3,0]],
       "temperature models":[{"model":"uniform", "temperature":293}],
       "composition models":
         [
           {"model":"uniform", "compositions":[0], "max depth":50e3}
         ]
    }
  ]
}