Keystone of an Arch, Frontal View and Profile; verso: Sketches of a Ground Plan and a Nude Male Figure

Colored crayons on paper

Graphite on darkened off-white tracing paper

Colored marker on paper

Black crayon on paper

Watercolor over graphite on off-white wove paper

Graphite on paper

Pastel on cream card

Graphite on paper

Black and white chalk on rough beige antique laid paper, framing line in brown ink

Charcoal, graphite, and white chalk on blue wove paper

Graphite on off-white wove tracing paper

Colored marker on paper