5- XII Biennial of Sao Paulo, 1973. Grand Prix de la communication: 10 telephones installed on stands allow the public, who was informed by small advertisements in the daily press, to communicate vocal messages, that were amplified by large loudspeakers, in the enclosure of the XII Biennial of Sao Paulo. It is a device of free expression that the military system at the time would do its best to prohibit. (Various pressures ended in the arrest of Fred Forest)