hello !
Im showing you how to make a duplication glitch and have alooot of items. This works with every stackable item. you must put at least 2 same items in the dispenser to get 2 more out of it. if you put 64 Stone in it. it will throw you 64 stone and there will be 63 left in the dispenser. This may not work on every server. I tried it on my own server and it didnt work. But it worked on my friends server.
The way you do this is you put 2 dispenserd next to each other with a block of air betwen. Put a lever on that place. Put items in the dispenders and flick the lever. I made a item farm with this bug and im using it on friends server.