I'm reading Bring Me the Rhinoceros by John Tarrant, who presents a number of Zen koans and associated stories. He quotes Emily Dickinson in one of the chapter headings:
"Friday I tasted life. It was a vast morsel. A Circus passed the house - still I feel the red in my mind though the drums are out. The lawn is full of south and the odors tangle, and I hear today for the first time the river in the tree."
This strikes me with great force every time I pass my eyes over it. It is like a hallucination or a peek into the world of an alien mind. I can't make logical sense of it, but it seems true, and it makes reality seem more real.
I guess this is what koans are supposed to do.