This object consists of a black cardboard box with a black tube affixed perpendicular to its facing side and to the left (see photo). Inside the box is an electric buzzer whose switch is located on the left-facing side of the box as it hangs from the wall. On the front of the box, to the right of the tube, is an instruction sheet which invites the visitor to participate in the action "Cannon." In order to do so, the participant must look into the tube and simultaneously switch on the "device" with his left hand.
When the participant switches on the "device," instead of the expected visual effect, the sound of an electric buzzer is heard inside the box (change of perceptual paradigm).