To introduce a new line of hair products, Apotek Hjärtat, a Swedish pharmacy decided to give subway commuters in Stockholm a surprising special effect. With the help of their ad agency Akestam Holst, they fitted digital screens on the subway platform with ultrasonic sensors that discerned when a train was coming.
The pharmacy ad then featured a model with a lush mane. When the train arrived the sensors immediately simulated the blowing in the wind effect for her hair.