def urbanmain() = {
  import M5a._

  val urban_generate = 
    """+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++.[-]++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++.[-]+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++.[-]"""

  assert(generate("ABC".toList) == urban_generate)

}