When a coaster is constructed, it's usually to a set of plans and engineers will follow them and shape the wood as each part of the plan dictates.
A Plug'n'Play coaster (by Intamin AG) already has this done. The ride essentially arrives "flat pack", with a set of "insert A into C and tighten with bolt 9F" instructions. The engineers at the park have to simply put it together on a flat bit of ground.
While this makes the entire process sound very whimsical and simple, there's nothing whimsical or simple about the rides themselves. Highly engineered and designed to give maximum thrill and airtime, Plug'n'Play coasters are a coaster fanatic's dream ride.