GRAV – research group on visual art) – was not a group of researchers, but a group of artists doing research. It was active in Paris from 1960 to 1968. These dates may mean nothing or be totally unrelated to anything else – but 1960 is just one year before in Zagreb the first New Tendencies exhibition opens, and the group dissolves in the year of the climax of the post-war youth revolts in Paris, the rest of France and West-Germany, but also in the USA, not to forget the Prague Spring and its smashing by Warsaw Pact troupes.

Members of GRAV were, at times, called “opto-kinetic artists”. Among them were Julio Le Parc, Vera Molnár, François Morellet, Horacio Garcia Rossi, Francisco Sobrino, Joël Stein and Yvaral.

Yvaral’s father, Victor Vasarely, maintained and practiced the concept that the sole artist was outdated, a concept that appealed to the participation of the public. Such participation was not all that exciting: it meant, at a first such event in Paris in 1963, that visitors could walk through labyrinths arranged by the artists. This was certainly a predecessor of interactive installations.

Types of participation, as identified by the group, were:

- perception as it is today,
- contemplation,
- visual activation,
- active involuntary participation,
- voluntary participation,
- active spectatorship.

In 1963, GRAV published a manifesto, Assez des Mystification (“Enough of Mystification”). There they stated:

“If there is a social preoccupation in today’s art, then it must take into account this very social reality: the viewer.

To the best of our abilities we want to free the viewers from this apathetic dependence that makes him passively accept, not only what one imposes on him as art, but a whole system of life… We want to make him participate. We want to place him in a situation that he triggers and transforms. We want him to be conscious of his participation…

A viewer conscious of his power of action, and tired of so many abuses and mystifications, will be able to make his own ‘revolution in art’."