“It is the architectonic gesture of the Virgin which accomplishes the miracle, as she pulls at her mantle with her left hand so as to enclose herself in an absolute pyramid which turns, an unmoved mover, on a crystalline pivot, until is establishes before us the ideal axis which, etched in the fold on the forehead, runs down the protruding part of the face and descends past the closed edge of the drapery as far as the jutting corner of the pre-Dieu. But the right hand advances at an angle, to test cautiously the possible boundary of the pictorial space; having found it, it halts; while, counterbalancing it, the book slices the air with the sharp blade of its bright page. In the hollow within the column of the neck, there slowly settles the enclosed ovoid of the face, over which turn, as over a planet, broad diagrams of regular shadows.”

(Roberto Longhi, from “Piero dei Franceschi e la pittura veneziana”, quoted (and translated) by David Tabbat in his introduction to Three Studies, pp. xiii–xiv)