The difference in the size of the cells on the calyx under the vexillum right down to the common peduncle is conspicuous.
"More Letters of Charles Darwin Volume II" by Charles Darwin
Vexillum magnum, basi simplici nec auriculata, late ovatum, acutum.
"Expedition into Central Australia" by Charles Sturt
Jussit proeterea Gabrielem vexillum laudis supra Meccanum Templum explicare.
"Thalaba the Destroyer" by Robert Southey
Let us consider a pair of opposite hole (αααα’, αααα), for instance (2’, 6), and look at a Roman vexillum through the dodecahedron, holding it with αααα’ and αααα parallel, and αααα’ near an eye and αααα opposite. If the dodecahedron is close the eye, we see the two holes. If it is too far, we can see just hole αααα’.
Roman Dodecahedron as dioptron: analysis of freely available data