While Matthias of Arras was schooled as a geometer, thus putting an emphasis on rigid systems of proportions and clear, mathematical compositions in his design, Parler was trained as a sculptor and woodcarver. He treated architecture as a sculpture, almost as if playing with structural forms in stone. Aside from his bold vaults, the peculiarities of his work can also be seen in the design of pillars (with classic, bell-shaped columns which were almost forgotten by High Gothic), the ingenious dome vault of new St Wenceslaus chapel, the undulating clerestory walls, the original window tracery (no two of his windows are the same, the ornamentation is always different) and the blind tracery panels of the buttresses. Architectural sculpture was given a considerable role while Parler was in charge of construction, as can be seen in the corbels, the passageway lintels, and, particularly, in the busts on the triforium, which depict faces of the royal family, saints, Prague bishops, and the two master builders, including Parler himself.