A conceptual drawing by Anton Heyboer, featuring geometric diagrams and handwritten notes that map his personal philosophy of the human psyche.

Anton Heyboer, a Dutch artist who spent much of his life in relative isolation in Den Ilp, developed a unique visual language to map his personal philosophy. This work, titled Psychologisch algebra, functions as a diagrammatic exploration of human consciousness. Heyboer utilised a combination of geometric structures, mathematical notation, and handwritten Dutch text to articulate his theories on the psyche, ego, and the collective unconscious. The composition is characterised by a series of intersecting circles and arcs, rendered in thin, precise blue ink lines. These geometric forms are punctuated by sequences of small, hand-painted orange circles, which suggest a rhythmic or numerical progression. The presence of handwritten annotations throughout the sheet provides insight into the artist's analytical process, as he attempts to quantify abstract concepts like love, ego, and the external world. The aesthetic is raw and unrefined, reflecting the artist's rejection of traditional academic constraints in favour of a highly individualised system of meaning. Heyboer's practice often involved the creation of these 'systems', which he viewed as tools for understanding the human condition. The work does not aim for decorative appeal but rather serves as a visual record of a private intellectual pursuit. The juxtaposition of clinical, diagrammatic lines with the organic, hand-drawn quality of the ink and watercolour creates a tension between the rational and the intuitive. This piece offers a glimpse into the internal world of an artist who lived outside the norms of contemporary society, documenting his thoughts with a sense of urgency and meticulous detail.