Module Checkit {
      \\ Inventories may have keys or keys/values
      \\ here keys are values too
      Inventory Alfa="Apple", "Banana", "Coconut"
      \\ key 30 has value 25, other keys have value same as key.
      Inventory Beta=100, 30:=25, 20, 5
      Print "Parallel"
      k=Each(Alfa)
      k1=Each(Alfa End to Start)
      k2=Each(Beta)
      \\ Parallel iterators
      \\ when one of them end then while end too.
      \\ so 5 not printed. Print 100, 25, 20
      While k,k2, k1 {
            Print Eval$(k), Eval$(k1), Eval(k2)
      }
      Print "Nested"
      \\ Nested iterators
      k=Each(Alfa)
      While k {
      k1=Each(Alfa End to Start)
            While k1 {
                  Print Eval$(k), Eval$(k1)
            }
      }
}
Checkit