You show a square tube with a cut out window at each end on one side. Then you take out a white die. The die is inserted into the tube, it fits snuggly. You can see the value of the die through the left hand window. You slide the die over to the other window and now the die has changed value. The trick can be repaeted wit all possible results. The die change value despite the fact that it fits firmly in the tube. YES you can also make the die NOT cj´hange value if you want. Only one die is used and it can be examined.