A broad-nibbed pen was used almost invariably in making architectural designs of cornices, pilasters, windows, also in plans for military engineering.
Sketches of tombs and edifices, intended to be shown to patrons, were partly finished with the pen; and here we find a subordinate and very limited use of the brush in shading.

Such performances may be regarded as products of the workshop rather than as examples of the artist's mastery.

The style of them is often conventional, suggesting the intrusion of a pupil or the deliberate adoption of an office mannerism.

The pen plays a foremost part in all the greatest and most genial creations of his fancy when it worked energetically in preparation for sculpture or for fresco.

The Louvre is rich in masterpieces of this kind--the fiery study of a David; the heroic figures of two male nudes, hatched into stubborn salience like pieces of carved wood; the broad conception of the Madonna at S.Lorenzo in her magnificent repose and passionate cascade of fallen draperies; the repulsive but superabundantly powerful profile of a goat-like faun.
These, and the stupendous studies of the Albertina Collection at Vienna, including the supine man with thorax violently raised, are worked with careful hatchings, stroke upon stroke, effecting a suggestion of plastic roundness.