DIM @environ$(12)
      @% = 4 : REM Column width

      REM Initialise:
      FOR E% = 1 TO 12
        PROCsetenvironment(@environ$(E%))
        seq% = E%
        cnt% = 0
        @environ$(E%) = FNgetenvironment
      NEXT

      REM Run hailstone sequences:
      REPEAT
        T% = 0
        FOR E% = 1 TO 12
          PROCsetenvironment(@environ$(E%))
          PRINT seq% ;
          IF seq% <> 1 THEN
            T% += 1
            cnt% += 1
            IF seq% AND 1 seq% = 3 * seq% + 1 ELSE seq% DIV= 2
          ENDIF
          @environ$(E%) = FNgetenvironment
        NEXT
        PRINT
      UNTIL T% = 0

      REM Print counts:
      PRINT "Counts:"
      FOR E% = 1 TO 12
        PROCsetenvironment(@environ$(E%))
        PRINT cnt% ;
        @environ$(E%) = FNgetenvironment
      NEXT
      PRINT
      END

      DEF FNgetenvironment
      LOCAL e$ : e$ = STRING$(216, CHR$0)
      SYS "RtlMoveMemory", !^e$, ^@%+108, 216
      = e$

      DEF PROCsetenvironment(e$)
      IF LEN(e$) < 216 e$ = STRING$(216, CHR$0)
      SYS "RtlMoveMemory", ^@%+108, !^e$, 216
      ENDPROC