Module Checkit {
      Function Agm {
      \\ new stack constructed at calling the Agm() with two values
            Repeat {
                  Read a0, b0
                  Push  Sqrt(a0*b0), (a0+b0)/2
                  ' last pushed first read
            } Until Stackitem(1)==Stackitem(2)
            =Stackitem(1)
            \\ stack deconstructed at exit of function
      }
      Print Agm(1,1/Sqrt(2))
}
Checkit