What kind of bond is generated by the meeting between an art work and the observer? Filmed entirely at Arte Sella, the ecological art park in Trentino, Art Coefficient 07 – part of a broader study into the relationship between art works and spectators – documents the encounter between the work “Tana libera tutti” by Patrick Dougherty and Graziano, a former teacher passionate about the mountains. The setting for the meeting is the natural environment of the Val di Sella in winter.