types
  MyInt = int [2..100];
  LengthInt = int [0..40];
  Primes = autocons system
  |[
  var
        initialized : bool = false ;
        primes : list [ 40 ] of MyInt = [3]
  actions
    obs init = requires initialized = false :
      primes := [ x | var x: MyInt & (forall tmp : MyInt : 
            (tmp < x => (x mod tmp <> 0 )))  ] ;
      initialized := true end;

    obs Prime(a: MyInt) =
      requires (exists i : LengthInt : (primes[i] = a)) :
        skip
      end

  do
        init() // var A : MyInt : Prime(A)
  od
  ]|
system
        Primes