Conceit: extended metaphor, hard won.

This overcast windscreen,
a toad's bumpy rump,
ripples and blinkers all else.
He uses his tireless legs to smooth his skin
but like old age
the sifted rain continues
to dimple his flesh
slowly and steadily
a gentle timpani
beating his spurts of youthful vigour
sprinkling wrinkles on skin
becoming a toad.