In 1969, Prini was invited to participate in the exhibition, Op Losse Schroeven: situaties en cryptostructuren, at the Stedelijk Museum in Amsterdam. The artist renounced to presenting a work inside the exhibition space and instead carried out an artistic gesture in a sand field located outside the museum. Together with Marisa and Mario Merz, Pier Paolo Calzolari, Paolo Icaro, Jannis Kounellis and other friends, they pitched a series of tents to create a relational space—with the environment and for the exchange of ideas between artists. He invited participants to compose sentences, indicating reciprocal dependence, using candle wax:“Talk to him about his electric field and think of yourself as energy”. The entire process was broken down into bullet points and transcribed onto a sheet of paper by Prini. He planned to transplant the topographical correspondence of the field’s perimeter into the museum gallery and to install microphones on the ceiling that would emit the intentions—thought and written—by the participants. Among the points listed in the programme is the creation of a series of photographs of people captured from behind, sitting in their designated seats, in the field, with the back of their heads in the foreground.