This mod is very useful for building maps as it lets you clone chests and command blocks and their containing items, blocks or commands. If you find yourself often rewriting commands or similar tasks then this mod is suitable for you. This actually appears to be an official feature for the PC version of Minecraft.
How does it work?
In this first example I am going to clone a command block. You can insert any type of command and in this case I added a command (/time set 15000) which will set the time of day to night.
Close the command block window and then tap on the block with an iron sword to clone it.
As soon as you’ve done that you will receive a new command block in your inventory. It’s an exact copy of the previous one. To demonstrate this I placed it down on the ground and accessed the command block user interface. And as you can see, it does contain the text command which I previously added to the other block.
The same feature can be used for cloning chests. Place down a chest and then add whatever items or block you want. Tap on the chest with an iron sword to clone it.
Then place down the cloned block on the ground and it will contain all of the items and blocks you added to the original block.
Important: This is an addon which requires BlockLauncher which is a third-party app for Android.