The ticket-stamping machines are located near the entrance.

Perpetual motion machines are a fascinating concept.

Von Neumann machines are capable of self-replication.

Dynamo-electric machines have revolutionized the way we generate electricity.

Ground effect machines are used for transportation over water surfaces.

Ground-effect machines are used for transportation over water or rough terrain.

The heart-lung machines are used during open-heart surgeries.

I have two telephone answering machines at home.

Reverse vending machines are becoming more popular in recycling centers.

I saw two forwards time machines at the science fair.