Wave on wave of them settling,
close ranks shuddering into a dense, bristling glitter
of shields and spears and helmets – quick as a ripple
the West Wind suddenly risen shudders down the sea
and the deep sea swell goes dark beneath its force –
so settling waves of Trojan ranks and Achaeans
rippled down the plain.

– Homer

The Iliad, Book 7, lines 70-76. The Trojan and Achaean armies momentarily pause to listen to Hector address them. An extended simile likens them to waves on the sea, rippling and turning dark as the West Wind suddenly blows over them.