What would be the most useful invention?

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Teleportation Machine used to send anything from one place to another place instantly - Cell Regeneration machine used to make all living animal and human parts for transplantation - Time Machine used to allow a person to travel through time - Replicator device able to make anything you want that is inanimate/ nonliving - Holodeck room used to project a 3d holographic environment for entertainment, training, simulations, etc - Anti-gravity flying car a transport vehicle that can fly/ move without the need for roads - Free-Energy device device that pulls energy from hyperspace or vacuum; the amount of energy would be limitless