Jef Verheyen is known as a painter of light and colour, but he was also inspired and guided by the principles of geometry, as explained in the publications of Matila Ghyka, Le nombre d'or and The Geometry of Art. Following Ghyka’s theories about the golden mean and mathematical proportions, Verheyen wanted the paintings to emerge from the wall, like a window, and used different frames for every period. In the many sketches and studies Verheyen made for himself, one can notice the compositional principles behind his paintings. In the same way as he strove to transcend the materiality of colour and achieve effects beyond objective reality, he sought to use geometric structures to represent universally ordered connections. He used different kinds of structure to produce widely differing effects. In some works, he created harsh contrasts of shape and colour. In others, he integrated geometric shapes in such a sophisticated way that the viewer had to look twice in order to perceive them. Sometimes he divided the picture plane by a diagonal line leading from the corners to the interior space of the painting, or he integrated optical illusory geometric shapes. The combination of forms and colours created a suspenseful interplay, with the colours seeming to vibrate and sway back and forth.