Extending the figure-ground visual paradox to a fundamental architectonic problem - that of the reciprocity between a wall and a window - this book by Mauricio Pezo and Sofia von Ellrichshausen reflects on the intersection between painting and architecture. If a window is inherently a subtraction of a wall's surface but also an infill with a 'view' beyond it, a painting is as much a flat, opaque surface as the illusion of space beyond.