My calculus teacher
explained asymptotes like this:
Imagine a line, yourself,
one stride away from that line. Take a step.
Another—but each time close
only half the distance. You could journey
forever. When summer sets in the north,
monarch butterflies skirt
the Sierra Madre, wing 2000 miles
to Mexico. It's an orange commotion Doppler reads
as weather. They arrive
on the Day of the Dead, day
of the dancing skulls. Fishermen
draw nets through night air to usher
the returning. In the Oyamel Forest,
monarchs weighing less than paperclips
vault into a cathedral of wings, cling
to warm wood and needle for months
before flying north,
dying—lifespan, the length
of their most necessary journey.
One down, forty-seven more, you wrote.
You finished your manuscript, and I was on a train
between two stations when your migration
ended. We had traded poems. You urged me
to cut the last line.