Duplicate glitch

There is a duplication glitch. If you place a button then three red stone repeaters forward. One red stone. Three repeaters to the left. One red stone dust. Then finally you place 3 more repeaters to the left and sticky piston with a chest .you have completed the duplication machine. 

 

Press the the button and then immediately click the chest. As the piston gets powered you must take an item out of the chest. If you do it correctly the item will appear in your hand and the chest.

 

it also works with shulker boxes