The Swedish Post has a collection of pre-stamped parcels that makes it easy to send things. The task for ad agency Akestam Holst was to tell people that it was possible to send almost anything over night with these pre-stamped parcels.
So they packed 80 parcels with all sorts of stuff and then recorded 80 specific sounds. These sounds were then used to launch what they called ‘The Sound of Green’ competition. Here the users had to pick a parcel and pay close attention. If they could figure out what was inside, the Swedish Post would send the same parcel to the winner the very same day.
After 140 240 guesses the competition finally came to an end.