A loudspeaker is positioned on the second floor inside a building.
A performer stands outside the building with a microphone in his hand.
When the performer is ready, they throw the microphone inside the building, trying to get it through the window and land it as close to the loudspeaker as possible.
When the microphone lands inside the building, it triggers a sound feedback.
The audience can split up and watch the action from either outside or inside the building.