Fra Giovanni's Intarsia Polyhedra
Intarsia are mosaics made of pieces of inlaid wood. They are a remarkable
art form which reached a peak in northern Italy
in the late 15th and early 16th centuries. Many outstanding
examples of this period feature polyhedra. Below are four intarsia
panels by Fra Giovanni da Verona, constructed around 1520. The first
pair is in the Monastery of Monte Olivetto Maggiore (near Siena) and the
second pair is from the church of Santa Maria in Organo, Verona.
The first features a 72-sided
sphere, a mazzocchio, and various instruments of the geometer.
The second features an "elevated icosidodecahedron," a complex nonconvex
polyhedron which can be constructed by erecting a pyramid of equilateral
triangles on each face of an icosidodecahedron. The use of the mazzocchio
goes back to Uccello. The other polyhedra
are based on Leonardo's drawings of "solid
edge" models, published in Pacioli's influential
1509 book The Divine Proportion.
Note that intarsia are flat panels. The appearance of open cupboard
doors is a trompe l'oeil effect of the masterful perspective. The
same effect is used in others of Fra Giovanni's panels. The next
one below features the same 72-sided sphere, along with an icosahedron
and a truncated icosahedron. The panel after that features a cube with
equilateral pyramids erected on each face, a cuboctahedron, and again the
To construct intarsia, outline drawings are used as templates for cutting
many pieces of wood (perhaps a thousand or more in these examples).
The cut wooden pieces are glued to a wooden substrate and varnished.
Different colors of wood provide the different shadings used. Sometimes
stains, bleaches, or heat were applied to the wood to provide a wider range
Leonardo's printed drawings were clearly used to provide the outlines.
The identical viewpoint and perspective is used in each case, but Giovanni
skillfully rotated the images and and adjusted the shadings appropriately.
examples above were all influenced on Leonardo's drawings in Pacioli's
book. However, there were many spectacular intarsia before that time.
At right is one earlier example, featuring a mazzocchio. It is just
one panel from the richly intarsia-ized Studiolo of Urbino, in the
Fra Giovanni's work is the most impressive of the art in my opinion.
Intarsia then died out as an art form in the mid 1500's. This was
part of the general trend away from geometric perspective, but also because
the technique was denigrated as a "craft" compared to the "art" of painting.
References: See the article by Tormey
and Tormey and the book by Cromwell. The first two images above were
scanned from the Tormey article, and the third and fourth were sent to
me by Peter Cromwell.