type Query {
  myField: InterfaceType
}

interface InterfaceType {
  subField: SubFieldType
}

type OnePossibleConcreteType implements InterfaceType {
  subField: SubFieldType
}

type SubFieldType {
  subSubField1: String!
  subSubField2: String!
  subSubField3: String!
  subSubField4: String!
}