Tutorials/Block and item duplication

This page seeks to teach you how to clone items and blocks without building a separate farm for them, in vanilla Survival mode. It can be treated as an "everything farm," since it can "farm" things that can't normally be farmed, like block of diamonds, dragon eggs and other non-renewable blocks.

If any of these do get patched, you must either go back versions or use third-party applications in order to replicate them again. For Java Edition, this can happen in the Minecraft Launcher, but on Bedrock Edition, you must use third party applications in order to replicate these again. These third-party applications are NOT owned or endorsed by Mojang, so use at your own risk.

Note that these techniques are considered "cheating" by many people and Mojang tries to remove the ability to duplicate in Survival during almost every update. On some servers, these techniques are bannable offenses.

The best way to duplicate a block is to turn it into an item first, then duplicate the item. However, there are other ways to duplicate the blocks themselves, though they only work for certain blocks. Shulker boxes make item duplication much easier because they allow for up to 1,729 items to be cloned at once (including the shulker box).

Uses

 * Duplicate your most valuable gear: if you lose them to lava or the Void, you can just pull a backup from your backup chest! More specifically, you make a duplicate from your backup, so you can go through the entire process if you lose them again.
 * Duplicate Enchanted Books / Diamonds / Ancient Debris / Netherite Ingots / Emeralds: Once you have one, you'll have an infinite amount by duplicating it. Again, it is important to leave some stock as backup; you never know if you need more.
 * Duplicate Enchanted tools / Blocks: You'll never have to worry about running out of your tool / block of choice, since you can just duplicate them as well. Duplicate in bulk for items/blocks that will be used in large quantities.
 * Duplicate Shulker Boxes (with items inside): theoretically you can duplicate both the shulker box and the items it contains, since that info is stored within the shulker box itself. Use this to duplicate blocks in excessive quantities.
 * Duplicate Enchanted Equipment: combined with a grindstone, you can farm an infinite amount of EXP by removing enchantments from duplicated enchanted gear. While a decent, safe and consistent method of getting exp, building an Enderman Farm is faster.

If you happen to be a speedrunner, duplication if allowed can cut down a lot in your game time. One extreme example is the TAS Any% speedrun done in 29.41, complete with the dragon dead. Alt+F4 is usually used for this purpose.

Legitimate Duplication
These are not actually duplicating items, but instead are legitimate (or mostly legitimate) methods of obtaining certain items.

Dirt Duplication (Both editions)
Start by obtaining at least 2 dirt and gravel from bartering. Next, craft coarse dirt using 2 dirt and 2 gravel for 4 coarse dirt, then till the dirt and mine it to obtain 2 extra dirt. With a bartering farm, a good hoe, and a good shovel, you can mass produce dirt in a matter of minutes. However, this is not perfect duplication, as you will need a constant supply of gravel.

Infinite villager trading 1.16+ (Multiplayer only)
This is known to work in vanilla 1.16.5, but has been patched in Paper. Certain items can be obtained abnormally quickly from villagers at only a small price of a very abundant tradeable resource (like sticks).

Unpatched/Working
Currently, work as of the latest release of vanilla Minecraft. They may be patched in modified servers (such as Spigot, or Paper), which many servers use, but have been tested and they still work in unmodified conditions. In singleplayer, these will work but in multiplayer, these will usually not work.

Basic Save File manipulation
This method is safe and reliable. Needs only the desired items for duplication as well as a chest. You need to have access to save files so this is impractical on servers, where admins aren't giving FTP out like candy.


 * 1) Have the desired items to be duplicated on you: whether it's in your inventory, on your hotbar or equipped doesn't matter.
 * 2) Exit and save the game - returning to the main menu is quickest.
 * 3) Navigate to your save folder. On Linux, this is located at , on macOS it's at  , and on Windows, it's at.
 * 4) Making a backup folder of the target world folder is advised but unnecessary.
 * 5) Open the target world folder and duplicate the   and   files.
 * 6) It is advised you keep the duplicates in a place easy to access, usually the world save folder itself. This especially applies if you plan to duplicate items multiple times.
 * 7) Alternatively, have multiple folders on screen to simply select, copy and paste from one to another.
 * 8) Enter the target world and deposit the desired items to be duplicated into a chest.
 * 9) Exit the world and return to the main menu; the game should save.
 * 10) Copy and paste the duplicated   files back into the target world folder.
 * 11) Enter the target world. The desired items should both be in the inventory and in the chest.

Extra info: these files also contain your current location and your exp. Theoretically, you can enchant some gear, deposit it in a chest, then load the level.dat file to preserve your level and keep the enchanted gear. Another potential use is to use up your inventory while building then load a backup to keep your progress and refill your inventory with the building material. You could even use this to try multiple times to kill the Ender Dragon / Wither without risking your gear and inventory.

Disclaimer: the environment and mobs are not saved with this method, do not attempt to summon the Wither near places of importance or important mobs. Instead, backup the entire target world folder and load it in event of failure. Perform test runs to ensure that this method works.

Alt+F4 v2.0 - Task Manager
Alt+F4 is patched, but using Task Manager to end the task, on the other hand, is NOT patched, and still works. This is very similar to the Alt+F4 method. Steps:

From testing, it doesn't always work. Try playing with different timings. Video here:
 * 1) Open task manager
 * 2) Go into the world you want to dupe the items in
 * 3) Make sure 'Pause on Lost Focus' is off - Do this by pressing F3+P until you see something like "[Debug] Pause on lost focus: disabled" in chat
 * 4) Put the items that you would like to dupe in your inventory
 * 5) Close the world and open it up again
 * 6) When it loads drop the items on ground by pressing 'Q' on the item. Don't close your inventory.
 * 7) Quickly press ALT+TAB or  CTRL+SHIFT+ESC to get into Task Manager
 * 8) End the process "Java(TM) Platform SE Binary"
 * 9) Open Minecraft and load the world again
 * 10) Collect your items

Unpatched 1.16.5 MULTIPLAYER duplication (Explosive fireworks + elytra)
This duplication glitch works on 1.16.5 multiplayer. It requires an elytra and firework rockets that deal damage to the player. If the rockets do not damage the player, the duplication will not work. Video below: (duplication glitch starts at 0:33)

This is known to work in vanilla servers and realms, however Spigot has patched the bug and Paper has patched it long before its discovery.

Dirt Duplication
The mechanism for growing giant spruce trees is known to be glitched in JE 1.16 snapshot. Instead of growing a giant tree on the saplings, the game grows the tree on the first position where space is sufficient and a dirt block is present in the north-west position. When the tree is grown, all the dirt blocks are filled in. With bone meal and piston automation, a semi-auto dirt duplicator can be produced (YouTube by ilmango).

Lead Duplication(note: does not work in 1.16.4)
Bring an animal to the end, put a lead on it, and then lead it into the end portal. When you get back, it should have dropped two leads. Sometimes one of the leads ends up in the end, so make sure to check there. It may not always be in the end, though. This also works when bringing animals into the nether.

ALL Item Duplication Glitch (Patched on spigot & paper)
This duplication glitch works on Singleplayer and Multiplayer. All you have to do is place a chest in front of you and then leave the server as it saves your player data, then relog and put the items you want to dupe from your inventory in the chest, get a book and quill, overload the book with excessive characters and it will cause you to get kicked from the server and rolling back your player data to last save while server files stay the same. As a result, the items will be in both your inventory and the chest. (requires fabric download and custom download to work) Video here: https://youtu.be/ml3HkqNfUH4

Carpet Duplication Glitch
This glitch gives infinite fuel and is very easy to automate give thousands of carpets per hour tutorial: https://www.youtube.com/watch?v=mGQLDJ8dNGs

Dragon's Breath Duplication
Whenever the dragon lands on the end portal and releases the purple fog, be above or below the purple fog, look at the fog at a steep angle, and proceed to harvest the dragon's breath. The fog will first shrink as intended, but after it reaches the smallest size, it will expand with each bottle used, and keep expanding until the fog disappears as too much time passed. (YouTube by Underscored Frisk)

Using Shulker Boxes (Patched on spigot)
Shulker Box dupe allows you to duplicate any item in Minecraft singleplayer or Realms. This glitch works with 2 players or with an auto mine mod. So you quickly spam your item in and out while it being broken. The key is to take the item out just before the shulker box breaks. This may take a few tries but eventually you will dupe your items.

You can also use autoclicker with these settings: time between clicks- 1sec 487milisecs. Then you bind the autoclicker to key n, and automine to key m and press n,m,right click at the same time. This opens shulker. Hover over item you want to duplicate - shulkerbox should break and item in it, and item on the ground.

Video here https://www.youtube.com/watch?v=mGQLDJ8dNGs

Carpet Duplication
Carpets can be duplicated using a contraption made of two Slime Blocks, a Sticky Piston, and an Observer. This method works for singleplayer and multiplayer. Video here https://www.youtube.com/watch?v=mGQLDJ8dNGs

Patched (Paper)
These item duplications work in vanilla servers and Realms, but many servers use a modified server software called Paper for many reasons, including swiftly patching many exploits. Here are many block duplication methods that will not work on recent builds of Paper but work fine in vanilla.

Rail/Carpet Duplication (Unpatched in Paper Build #358)
https://www.youtube.com/watch?v=U-9ihB7EmKI and https://www.youtube.com/watch?v=mGQLDJ8dNGs&t=3s are in-depth tutorials that show how to do so

TNT Duplication (Patched in Paper 1.15.2 Build #350)
TNT duplication works in a similar way as rail duplication. A TNT block is BUD-powered, such that when the contraption is pushed by a piston, the TNT is updated and ignites into a primed TNT entity. Then, the piston moves the TNT from the list of TNT block left. This doesn't so much duplicate the TNT block as it creates free primed TNT entities from it without deleting it. Many TNT duplicators still work, but unless properly constructed will blow themselves up. TNT duplication is unreliable and will fail sporadically. This appears to have been patched in version 1.16.4

One common TNT duplication design uses a minecart on a detector rail to power the slime block it is placed on, and moves a TNT block next to a coral fan underneath, the combination of the TNT and the coral duplicates the TNT whenever the whole contraption is moved forward with a piston.

The second slice may be placed on either side, and the coral fan has been marked with vines. To prime the mechanism, the upper slime blocks must first be moved forward, pushing the TNT under the rail. After this, moving the whole assemblage forward with a piston will duplicate the TNT, spawning a lit TNT entity directly below the TNT block.

Gravity Block Duplication (Patched in Paper 1.15.2 Build #358)
There are many ways to do this, but the basic idea is the same.

A gravity-affected block is pushed toward an end portal. It becomes an entity as it falls into the portal, and it travels into the other dimension's "spawn point.", but before it's removed from the original dimension, it bounces off an entity in the portal (in a vehicle so it won't go through), and is caught by some pistons. It then turns into a block and is returned to its original location. This process can be looped using redstone. It works for any block that is affected by gravity, except for primed TNT because it would blow up the contraption and cannot become a block again in any case.

Dragon eggs and anvils fall differently from each other and other gravity-affected blocks such as sand, gravel, and concrete powder. Neither dragon eggs nor anvils work in a sand/gravel/concrete powder duplicator because of this. However, it is possible to create a machine that can duplicate dragon eggs and anvils but not sand/gravel/concrete powder. They both can be duplicated and sent into the End as either falling entities or items.

Tripwire Hook Duplication (Works vanilla 1.16.3) (Patched on Paper)
Tripwire Hooks are duplicatable, but only in certain directions. It may work in some directions, but not others.

Patched/Non-Working
These no longer work as of the latest release of vanilla minecraft, but worked on older versions.

Singleplayer
These are dupes that only work(ed) on singleplayer, either because you need access to manage the server, Paper/Spigot patched it, or most servers have plugins that let it not work.

Alt + F4 Method (Patched 1.13)
This method is a simple method and has been around since the beginning of the Alpha stage. This method involves dropping the items you want to duplicate, and then saving and quitting. You would then reload the world, pick up the items and press the keyboard shortcut to close a window. Then relaunch the game and reload the world. The items should be duplicated.

Multiplayer
These are dupes that only work on multiplayer, commonly because they exploit an anti-dupe plugin (like the thousands of donkey dupes)

Deadly Method (Patched 1.15)
This method is extremely deadly, but not necessarily to the player. This method involves taking a mob that can carry items (e.g. a zombie, a donkey or a llama) down to very low health (i.e. half a heart or less). Using extremely precise timing, kill that mob as it travels through an end portal or nether portal. The items equipped and the mob should appear in the other dimension. It works by tricking the game into thinking the mob is alive on one end of the portal and dead on the other side. The live mob will travel through the portal still carrying the items, and the dead mob's items are also sent into the portal, allowing the player at the other end to collect the cloned items and the mob carrying them.

The deadly method used to automatically farm diamonds (currently the fastest theoretical means of automatically obtaining items in vanilla survival):

Same Player Twice (Patched in virtually every server)
There is a way to trick the game into logging in the same player twice on one server. To do this, start two instances of Minecraft. This requires starting a new instance of the Launcher so that they don’t interfere with each other. Log them both on the same server at the same time. By doing this, the game will render two of the same player. You can then kill the copied player and double your inventory. Rarely servers may also duplicate players on accident or leave "ghosts" of logged out players which can be killed for the same effect.

Donkey Inventory Oversight (Patched in 20w16a and in Paper/Spigot 1.15.2)
Working in 1.15.2 and in 1.16 snapshots up to 20w12a (Patched in 20w16a and in paper). You need a tamed donkey or llama equipped with a chest. If a player shift-clicks the donkey / llama, that player may view the donkey's inventory and place items. If a second player rides the donkey, the first player will continue to view the donkey's /llama's inventory, even though it is not normally possible to view a donkey's inventory when it is already being ridden by a player. If the second player disconnects, the donkey will disappear along with them, and the donkey's inventory will be considered by the game as part of that player's data. However, the game will keep a copy of the donkey's inventory and GUI temporarily loaded for the first player, who can then reclaim the items. When the second player reconnects, the donkey's inventory will contain what was originally in it before the second player disconnected. The items can once again be taken from the donkey's inventory, resulting in x2 duplication.

Both
These dupes work(ed) everywhere! Servers that don't use anti-dupe plugins, singleplayer, etc.

Bundle Duplication (20w45a to 20w48a)
For any crafting recipe that uses more than 1 of the same item, you can use this dupe. To use it, you put the items in the crafting grid, then use the bundles on the crafting slot. The resulting item will not disappear but you will save the item you just took from a bundle. For example, if you used 9 stacks of netherite ingots to make 1 stack of netherite blocks, you could use 9 bundles to take all the netherite away and get 1 stack of netherite blocks for no cost.

Baby Piglin Item Dupe (Patched in 1.16.3)
This dupe involves baby piglins. It is incredibly simple and it works in multiplayer. To perform this glitch find a baby piglin and drop his health down to a 1-hit kill (2 hits with a normal diamond sword should work). Then drop the item you want to duplicate to the piglin(e.g. a shulker box) then wait for the baby piglin to pick it up. After the piglin has picked up the item drop the piglin 1 gold ingot. While the piglin is admiring the gold, kill the piglin.

Zombie/Drowned Method (Patched)
This method exploits the fact that zombies can transform into drowned while they are dying. If you coax a zombie to pick up an item by throwing one at it and then kill it right at the moment that it converts to a drowned, the zombie will die and drop what it was holding but the newly spawned drowned will be holding a duplicate of the item. This can also work with husks transforming into zombies.

Ilmango shows a simple implementation for survival:

Chunk memory overflow (Patched 1.15)
When you overflow chunk memory, you will be able to freeze chunk. What this means is that changes on this chunk will not be saved and after loading it again it will return to the previous state. The best way to do this is to create books filled with about fifty pages of random Unicode characters and put it in a chest. There are mods for doing this automatically, but you can also do it manually by copying and pasting. You will need two different types of books for this to work.


 * 1) Choose a chunk in which you want to duplicate and do everything only in this chunk (Press F3 + G to see chunk borders).
 * 2) Get 22 books filled with random characters, name them "X" and 21 filled books but with other characters, name them "Y".
 * 3) Place a chest and put the items you want to duplicate inside it.
 * 4) Place a chest at the same chunk and put them in this pattern:
 * X|Y|X|Y|X|Y|X|Y|X
 * Y|X|Y|X|Y|X|Y|X|Y
 * X|Y|X|Y|X|Y|X|Y|X
 * 1) *You will have 8 books of each type left.
 * 2) Place a chest above it and put 8 of book X in slot 1 and 8 of book Y in slot 2 in that chest.
 * 3) Reload chunk by reconnecting to the world(if you are on singleplayer) or going 200-300 blocks away and returning(if you are on multiplayer)
 * 4) Move books from the second chest like this:
 * X|Y|X|Y|X|Y|X|Y|X
 * Y|X|Y|X|Y|X|Y
 * 1) Take out the items you wanted to duplicate into your inventory or put them in a chest at the other chunk.
 * 2) Reload chunk again.
 * 3) Now you have your item(s) in the chest and in your inventory. Books in a second chest are just like in [4].

In 1.14+:


 * 1) Press F3+G to see the chunk border.
 * 2) Place a barrel in the chunk that you want to duplicate. Then, place a chest above it.
 * 3) Then, put the items that you wanted to duplicate in the barrel.
 * 4) After that, put 25 book and quills that filled in with 100 pages of random unicode characters in the chest like this.
 * X = 1 book; Y = stack of 2 books
 * X|X|X|X|X|X|X|X|X
 * X|X|X|X|X|X|X|X|X
 * X|X|X|X|X|Y
 * 1) After that, press esc and select 'Save and Quit to title' to save the chunk (If you're in singleplayer) or walk 400 blocks away from the chunk (If you're in multiplayer, make sure of the other players were stayed in the nether else the duplication won't work). This method will save the chunk.
 * 2) Then, log-in your world again (If you're in singleplayer) or walk back to the chunk (If you're in multiplayer).
 * 3) Open the chest and move the books like this:
 * X|X|X|X|X|X|X|X|X</tt>
 * X|X|X|X|X|X|X|X|X</tt>
 * X|X|X|X|X|X|X</tt>
 * 1) Take your items away from the barrel and move them to your inventory or put them in a barrel at the other chunk.
 * 2) Save chunks again.
 * 3) Go back to the chunk again.
 * 4) Your items will reappear in the barrel. The books will be reverted to the state in step 4. Duplication complete.

Discovered by Earthcomputer:

Tutorial on YouTube by BarrenDome:

Dropped Items (patched 1.13)
Relogging at the same time as you drop items can dupe items. Needs very precise timing; exit the second you see the items but before you hear the sound of collecting items.

Piston Duplication (patched 1.16)
When an item frame is removed (broken by the player) from the rear of a piston as the piston is retracting, the correct timing will yield two items of the item that was within the frame. This will work with any blocks or items inside of the frame, with shulker boxes being able to duplicate multiple items at once. This method works in both singleplayer and multiplayer game modes.

Crafting Dupe (Patched 1.12.1)
1. put 2-3 stacks of planks in your inventory.

2. drop the item you want to dupe on the ground( make sure that there is no item that it can stack within your inventory)

3. open your inventory and spam the crafting table recipe until you pick up the item you dropped. It should result in a stack(even for non-stackable items)

Using Dolphins(Patched 1.17-pre2)
Put a dolphin in a nether portal as it absorbs an item. The original item will still be there, while the dolphin will carry a copy.

Dirt Chest (works 1.16.1+)
When using this method there might be a chance the items will get deleted, so creating a backup is recommended. This method will not work on Realms.

1. Gather all the items you want to duplicate as well as a chest.

2. Place your chest, and make sure there is 4 dirt in front of the chest.

3. Save & Quit, and then rejoin the World.

4. Place the items you want to duplicate in the chest and quickly break 4 dirt in front of the chest 1 y-level below it in a 2x2 square shape then count to 4.

5. Quickly forcibly close the application.

6. Rejoin the game. One of three things will have happened; A) The items will have duplicated (both in inventory and chest), B) The items will have been removed (neither in inventory nor chest), C) Nothing will have happened (in chest or inventory).

https://www.youtube.com/watch?v=ptGpINSxhaA

Chunk save stating
This method works by causing the game to crash in a way that only the chunk you are standing in will not save correctly, this will cause the chunk you are standing in to revert to the last save, allowing you to dupe in that chunk.

Explanation of how it works: https://youtu.be/XTkivXhbcMA

Beacon + Pocket Edition
This duplication is possible on realms, but only works with stackable items.

1. Get a beacon (It does not have to be activated).

2. Put items to duplicate in your Hotbar, the nine slots on your screen.

3. Open the beacon GUI.

4. Double-tap on the items you want to duplicate. You can't duplicate non-stackable items, and it only duplicates up to fill a full stack.

Note: This might only work if Settings > Video > UI Profile it is set to Pocket, not Classic.

Patched
To use the following methods, you will have to either not update past that point or revert to a previous update (if possible for your system, not all can, such as on Xbox One or Nintendo Switch).

Gravity Block Duplication (Patched on 1.16.200)
Duplicates all gravity-affected block except dragon eggs

This video will explain how to duplicate any gravity-affected block. It works similarly to gravity block duplicators $$: by having a falling block enter an end portal and become a block on the same tick.

The reason this design does not work for dragon eggs is that it relies on pistons being able to push blocks into their original position. This allows for the block to be duplicated repeatedly, every 6 redstone ticks. However, one can manually duplicate dragon eggs with a similar process:

In the above diagram, the G, D, and P denote the grindstone, dragon egg, and portal, respectively. The repeater is necessary for the timing to work correctly, due to. Like the automatic gravity block duplicator, one must use huge mushrooms to replace the End portal frames.

To use, deactivate the lever, and a second dragon egg will appear in The End. You can then re-activate the lever to break the dragon egg and place another one. This design can be used for other gravity blocks, but the automatic version is generally more efficient.

Another alternative to end portal based duping is end gateway based duping, however, it is not as fast as end portal based duping.

Anvil Duplication (Patched in 1.16)
You will need two book & quill and an anvil. Write any text in one book & quill, and sign it. From then, copy the first book & quill by placing them next to each other in the crafting grid. Take the item you wish to duplicate and rename it to the name of the copied book. From here, you can shift-click the anvil result and duplicate your item.

Anvil Naming (Versions 1.5.1-1.16.0) (Patched)
When naming a stack of items in an anvil, you can use the "Take Half" option to receive the output items without depleting the original stack. As long as you do not take the final renamed item, you can go to the original stack and pick it up to start more or just leave the anvil interface if you are done. Items duplicated this way won't work for quick use in a recipe, though certainly can be used for Classic crafting and any other use. However, if you wish to revert an item to the default name, you can do so by crafting it into another item then crafting it back to the original (such as redstone block -> redstone dust x9 -> redstone block), or by placing it as a block then breaking it back into an item.
 * A way to speed this up is to hit "Take Half", then "Toss Item" while standing close to the anvil, so you can rapidly go through a full stack without having to manually move each selection.
 * Sometimes a block won't lose its name when broken into an item, such as shulker boxes which are meant to keep their name, or just randomly the name may stay with a regular block and repeating the process will remove the name. However, some items may break into different items, such as an ender chest dropping obsidian, and the obsidian will each retain the ender chest's name (this was likely a glitch).
 * TNT Duplication
 * 1. Put a TNT anywhere
 * 2.Put a chest aside the TNT
 * 3.Put the item that you want to duplicate in the chest
 * 3.Light the TNT and at the same time the TNT explodes take out the item in the chest(this requires correct timing and good armor if you want to stay alive after the explosion)

Donkey + Looting sword (patched 1.16)
1. Get a donkey

2. Get a Looting 3 sword

3. Put a chest on the donkey

4. Put your items in that chest

5. Kill the donkey

The Looting 3 sword causes the donkey to drop more items than normal.

https://www.reddit.com/r/Minecraft/comments/g2k25b/this_bug_is_awesome_to_duplicate_your_items_put

Piston Chest (Patched in 1.16)
(Duplicates all Items)

When a chest is pushed by a piston, the contents are backed up a split second before it is moved. If you are in the chest interface and quick-move an item to your inventory in that moment then you will receive the item and the chest will be moved with the item still in it as well.

The recommended build is not automatic. For the recommended build, you will need at least 1 switch, 1 sticky piston, a chest, 10 redstone repeaters (all set to maximum delay), 2 redstone dust, and a button, though there are simpler(thus cheaper) versions that require only a sticky piston, a chest and a button. The instructions are as follows:




 * 1) Press the button.
 * 2) Wait until the piston pushes the chest.
 * 3) Open the chest, and immediately put your cursor on the block.
 * 4) At the last second, shift-click on the item you want to dupe.



If done correctly, you should have an identical copy of the item you put in.


 * If you can not afford to make a sticky piston, this method also works with one regular piston on each side. One piston pushes the chest, and then you open it. You then continue as normal, shift-clicking the item at the last second before the other piston pushes the chest back to it's starting position.


 * This method makes mass-duplication possible with the use of a shulker box and moving the contents of one duplicated box to the other, thus doubling how much you get each time, until you are duplicating an entire box's worth of items.
 * This does run the risk of massive lag in your world, by creating too many shulker boxes with contents. The effect may be even greater in online worlds such as realm servers. Be sure to transfer most items to regular chests after duplicating to avoid this.

Rapid Dispenser (Versions 1.5.1-1.5.2+)
(Duplicates some Stackable Items only) (patched)

This video will explain how to duplicate any item that can be crafted into a block using a dispenser and a redstone clock.

Bed Duplication (Patched)
Due to how beds are made out of 2 blocks, an explosion near the bed can make the bed drop 2 bed items, meaning you can spawn 2 beds (4 bed blocks) when you had 1 (2 bed blocks). You can repeat this and get infinite beds.

Ore Duplication (Patched)
Get an anvil and get either 9 iron ingot, 9 diamond, 9 coal, 9 gold ingot, 9 lapis lazuli, 9 redstone dust or 9 emerald. Rename 1 of the ores to something random, place it above the rest of the ores in your inventory and go to a crafting table. Craft a block of that ore and select 'craft all.' This will result in the player obtaining 1 block of (whatever ore you chose). The other 8 pieces will still be in your inventory.

教程/方块和物品复制