These stained-glass windows were intended for the sliding glass panels of the office of the Syndicalist Federation of Metal Workers on Crommelinstraat. Lebeau himself was an anarchist. He was awarded this monumental commission by his friend, the Social Anarchist, Albert de Jong (1891-1970). The two windows form a single composition. The worker on the right leans on a shovel and clenches his fist, as he urges a crowd of workers – men, women and children – to join the struggle.