1.   An employee then came out and escorted the client to an apartment with blacked-out windows, where tattoo machines buzzed in the back.

2.   Fax machines buzzed.

3.   Neighbors were glad to receive daily film schedules, though one complained when the snow-making machine buzzed too late at night.

4.   The fax machine is buzzing.

5.   The machine buzzes and beeps.