interface Shape
  method area() as word
end interface

class Box implements Shape
  byte b
  boolean ok
  char c
  word w
  integer i
  word[3] nums
  byte[2] flags
  Shape s
  Box next
  Shape[2] many
  Box[2] kids

  public method area() as word
    return 0
  end method
end class

class Empty
end class

program Main
end program