A favorite sonnet by Robert Frost:
I found a dimpled spider, fat and white
On a white healall, holding up a moth
Like a white piece of stiff brocaded cloth,
Assorted characters of death and blight
Mixed ready to start off the morning right
Like the ingredients of a witch's broth:
A snow-drop spider, a flower like a froth,
And dead wings carried like a paper kite.
What had that flower to do with being white,
The wayside blue and innocent healall?
What brought the kindred spider to that height?
And steered the white moth thither in the night?
What but design of darkness to appall?
If design govern in a thing so small.
I love the irony in line 5, and the overall shift from the scientific doubt in the octave to the moral outrage of the sestet — with the return to doubt in line 14. Note also the etymological force of "appall" in line 13 = "make pale".
(This picture of a healall (Prunella vulgaris) is blue rather than white; I couldn't find a white one. It's about a foot tall.)