Inside A Letter Box

Salvador Dalí, Gala. Miniature. Oil and collage on cardboard, 13.9 x 9.2 cm (5.51 x 3.54 in). Signed and dated lower center: pour loliveta (for the little olive-skinned one) Salvador Dalí 1931.

(Source: salvador-dali.org)

Charles Demuth.  I Saw the Figure 5 in Gold (To W.C.W.). 1928. Oil on cardboard, 90.2 x 76.2 cm. (inspired by the poem below)

The Great Figure, William Carlos Williams (1921)

Among the rain
and lights
I saw the figure 5
in gold
on a red
firetruck
moving
tense
unheeded
to gong clangs
siren howls
and wheels rumbling
through the dark city.

Source:The Poetry Foundation.

Joaquín Sorolla y Bastida, Apunte de Ibiza (Sketch of Ibiza). 1919.  Oil on cardboard, 20 x 24 cm. 

(Source: pintura.aut.org)

Jean-Joseph Benjamin-Constant, Glorification of Music (first sketch for the ceiling of the Opéra-Comique). c. 1898.  Oil on paper pasted on cardboard, 56 cm. diameter.