From Billy Collins' poem "The Butterfly Effect":

The one resting now on a plant stem
somewhere deep in the vine-hung
interior of South America
whose wings are about to flutter
thus causing it to rain heavily
on your wedding day
several years from now,
and spinning you down
a path to calamity and ruin
is--if it's any consolation--
a gorgeous swallowtail,
a brilliant mix of bright orange
and vivid yellow with a soft
dusting of light brown along the edges.