These works approach the student manifestations in 1977 and the violent reaction of the policemen and military forces against the students. In the first work- The Argumentof the Force: policemen threaten the students with blackjacks demonstrating the argument of force. In the second work - The Convincing Power: policemen beat a student demonstrating a kind of convincing power. In the third work - The Reason Above All: two students aid a third one, with hematomas provoked by beatings, and one of them points at the wounded one and screams in the demonstration that the reason is above the violence. In the fourth work - The Price of Freedom: the smoke provoked by a tear gas bomb involves a military policeman that threatens the students. The students' escape is provoked by the military contingent that is behind the soldier. On one of the students a dove, symbol of the non violence, rests.