Last November, British Airways unveiled billboards that interact with airplanes. Now, Swedish pharmacy chain Apotek has come up with some creepily-awesome subway ads that respond to incoming trains.
To promote a new line of hair products, Apotek snuck ultrasonic sensors into digital screens on a Stockholm subway platform. The sensors monitor the train's arrival, ensuring that the model's luscious tresses are blown away each time the train pulls in.
This video shows the installation process.
And here's some additional raw footage --which seems to suggest that timing the ad just right is a bit tricky. In this instance, the model's hair doesn't start blowing until well after the train first arrives.