https://www.pcgamer.com/this-minecraft-mod-makes-building-complex-structures-so-much-easier/

Building anything in Minecraft is an intensive task, and it's frustrating how few tools the game gives you to play with. Thankfully, modder Requios is here to save the day with their Effortless Building mod that comes packed with some incredibly useful tools so you don't have to assemble buildings one block at a time.

Using Effortless Building, players have access to a special menu screen full of options to speed up building by automating the process of placing blocks. The simplest tool is mirroring, which allows you to place multiple blocks at once but in mirrored positions. It's a bit complicated to explain, but watch the video above to see the mod in action. Essentially, if you're building a symmetrical structure (like a house), mirroring requires you to only build one quadrant of the house manually, with the rest being filled in automatically. It's very handy.