The exhibition 50 ans d’art moderne [50 years of modern art], held within the framework of the world exhibition ’58 in Brussels, was considered an eye opener for Henri Brouwers. Under the pseudonym Henri Gabriel he started as an artist in tachism and in paper clippings. Starting from these first optical works, he developed his spatially optical compositions from 1965 onwards. In the same year Henri Gabriel discovered kinetic art through the Parisian artists’ group Recherche d’Art Visuel and founded the group D.4, which was then renamed Geoform in 1966 with the arrival of Jo Delahaut. In the seventies he realized the dry-needle prints, Optical metal drawings. In 1978 he made the “Mobilo-sculptures”, a mix of mobile and sculpture.