THE MAGIC WOODEN CUBE

A SIMPLE TRICK MADE FROM A SOLID WOODEN CUBE WITH A CORD RUNNING THROUGH CENTRE OF CUBE.,THERE IS A KNOT AT EACH END OF THE CORD SO IT DOES NOT COME OFF THE CUBE.! CORD IS 16 INCHES LONG,AND CUBE IS 1 1/4 INCH SQUARE. WITH A HOLE 1/8 DRILLED THROUGH CENTRE OF CUBE.THE CORD RUNS FREELY THROUGH THE CUBE. NOW HOLDING THE CORDS AT EACH END UPRIGHT THE CUBES AT THE BOTTOM TURN IT AROUND HOLD THE CUBE AT THE TOP OF THE CORD,LET IT GO IT WILL DROP/SLIDE TO THE BOTTOM? BUT WITH A BIT OF MAGIC YOU CAN COMMAND THE CUBE TO STOP ANYWHERE ALONG THE CORD?? .THE CUBE CAN BE ANY SIZE UP TO 3 INCH AND THE CORD UP TO 3 FT .IF YOU WOULD LIKE TO MAKE THIS? WHAT YOU NEED IS A WOODEN CUBE SAY 2 INCH SQUARE A  DRILL BIT 1/8 AND A CORD SLIGHTLY SMALLER THAN 1/8.?? NEXT TIME I WILL SHOW YOU HOW ITS DONE. IN THE MEAN TIME CAN YOU WORK IT OUT HOW TO CONTROL THE WOODEN CUBE ON A CORD?? EASY WHEN YOU KNOW HOW??