types
  Class1 = autocons system
  |[
  var
	O2 : Class2 = new (Class2);
	flag : bool = false
  methods
	doSomething =
		flag := true
	end
  actions
	ctr init = requires true :
		O2.init(self)
		end
  do
        init
  od
  ]| ;
  Class2 = system
  |[
  var
	O1 : Class1 = nil
  methods 
	init (object : Class1) = requires (object <> nil) :
		O1 := object
		end
	end
  ]| 
system
        Class1 [] Class2