In Sonnet 44 he plays with impossibilities, like the Greek and Roman poets:
Ah me! the sea will have no waves, the snow
Will warm and darken, fish on Alps will dwell,
And suns droop yonder, where from common cell
The springs of Tigris and Euphrates flow,
Or ever I shall here have truce or peace
Or love....
and uses the same comparisons, Sestina 7:
So many creatures throng not ocean's wave,