The Cloning​ tool can be used to quickly build duplicates of rooms by copying and placing any area of land up to a 12x12 area. This costs the same amount of money as building it manually. The Cloning tool will not clone foundations or utilities. Only will clone things that are actually built.

Useful for building cell blocks and such, but be careful, as you may use a lot of money.

In Update 4 clone has been placed in the Quick Build menu and it will no longer require researching.