The life and work of Alfons Hoppenbrouwers (1930-2001), member of the Congregation of the Brothers of the Christian Schools, is characterized by great social and pedagogical engagement, coupled with an artistic and culture-based vision. In addition to being an architect, teacher and co-founder of the Sint-Lucas archive, he was also a visual artist. Out of his interest in Gestalt psychology, baroque music and architecture, Hoppenbrouwers developed geometric work in which he investigated how abstract oppositions - figure versus background - and cognitive arrangements of complex mathematical calculations generate form and arrange colour in the flat plane of plastic spatiality.