BlueDim in Dimension with
  dimcolor col: "0,0,210"
end

Element ParkType with
  potency
   BlueDim: 2
end

Element UrbanPark in ParkType with
  potency
   BlueDim: 1
end

UrbanPark->ParkType with
  dimension dim: BlueDim
end

Element CentralPark in ParkType with
  potency
   BlueDim: 1
end

CentralPark->ParkType with
  dimension dim: BlueDim
end

Element MyCentralUrbanPark in CentralPark,UrbanPark with
  potency
   BlueDim: 0
end

MyCentralUrbanPark->CentralPark with
  dimension dim: BlueDim
end

MyCentralUrbanPark->UrbanPark with
  dimension dim: BlueDim
end