When the scientist switched on the backwards time machine, she could only revisit moments she'd already lived.

The scientist cautiously activated the backward time machine to retrieve a lost manuscript.

The research team unveiled a prototype forward time machine that could only send people into the future.

He called her little brown fucking machine, and I immediately told him how offensive that was.

The customs declaration listed the cargo as an automatic data processing machine destined for the research lab.

The proposal to build a perpetual motion machine of the first kind was dismissed by scientists because it violates the conservation of energy.

Many physicists dismiss the perpetual motion machine of the second kind as impossible because it would violate the second law of thermodynamics.