1.   Attached to her khaki vest is a large plastic whistle.

2.   Between them, Kim Bok-soo, an illicit street vendor hawking small plastic whistles, was selling out quickly.

3.   Marijuana smokers on famed Ipanema beach are using plastic whistles to sound the alarm when police approach.

4.   Instead, it blew plastic whistles that have come to provide the piercing battlecry of the protest movement.

5.   The ubiquitous plastic whistle, available in any colour, has a lot to do with it.