The "Bassedanse" is a slow and majestic couple dance, which was practiced by the European aristocracy of the 15th century. Its choreography is organized around a very particular figure, called "Fantasmata", which consists of a momentary stop, a pause during which the body remains suspended between the accomplishment of a movement and the apprehension of the one that is to come. The figure begins with a lifting of the body just before the sole of the foot lands on the ground and marks the time. Once the movement is finished, a brief stop precedes a new lifting. Domenico da Piacenza, a dance master of the Italian Renaissance, describes the intention that should guide the execution of the fantasmata: "...to become stone in an instant, like someone who has seen the head of Medusa, then, in the next instant, to suddenly fly away like a falcon diving on its prey..." For Marina Nordera, a professor of ancient dance, Da placenza uses these metaphors to "draw the dancer's attention to the subtle floating between immobility and the initiation of movement. This moment during which the body becomes empty and is crossed, as if by a breath, by perceptive and dynamic images preserved by memory. Thus the fantasmata does not describe a passage to the inert, but designates "the set of conceivable differences between the mobile and the immobile: the break which separates them, the resonance which delicately links them, the moment when each prepares to change to become the other, the transitional gesture which authorizes the passage from one to the other." (Nicole Brenez).

Three silhouettes of dancers sketch out a choreography to the rhythm of three pendulums.

Beforehand, dancers were asked to move fluidly and continuously in front of a camera. The kinetic characteristics of their movements were recorded by the computer (motion capture). In "Fantasmata", the resulting computer data is recomposed rhythmically and randomly in real time, endlessly experimenting with the relationship between the mobile and the immobile. Tension, translation, slackening, leaping, sliding... The rhythmic pulsation of each pendulum controls the velocity of the silhouette enslaved to it, in every possible mode of transition from pause to movement and vice versa.

Each sculpture emits the sound of a clock. The slight desynchronization of the three pendulums generates an evolving polyrhythm of sound. Sometimes, complications arise in interaction or not with the spectators: the sound of the pendulums is interrupted and the silhouettes begin to evolve as if weightless, extremely slowly and in concert... At other times, additional mechanical sounds are emitted by the pendulums and the choreography becomes more complex... As different relationships are created between the three silhouettes, the spectator's perception of time changes.