Effortless Building Mod for Minecraft 1.12.2

Effortless Building Mod will significantly speed up the construction process, allowing you to copy in real time the structures you have built a number of times in the direction you need. You can also use quick block replacement.

How to install:

Download and install Minecraft Forge.
Download the mod.
Go to %appdata%.
Go to the C:\Users\User_Name\AppData\Roaming\.minecraft\mods folder.
Drag and drop the downloaded .jar file into it.
If one does not exist you can create one.
Play and enjoy!