Emblazoned across a video screen in graffiti scrawl were words and phrases from the libretto - it was an effective device.

In an effective device, their faces are contrasted - then and now - by juxtaposing archive footage.

A simple and effective device that transforms the building between day and night.

It also uses an unusual but effective device — clips of the interviewees once they have stopped talking.

The carport was therefore a cheap and effective device for the protection of a car.