Thirty/Sixty

We’re past the last time you were twice my age—
the charted course reveals convergent lines.
The numbers that were useful once as signs
to mark the passages from stage to stage
can only now report in roughest gauge
the broader trends and general designs:
to measure now, we need cosines and sines,
and tangents, whose division fills the page.

We calculate the tangents most of all—
the others are precise more than they’re true,
and we have little need for accuracy—
the tangents plot the lines that rise and fall
through points at which I deviate from you
to points at which you intersect with me.

Originally published in Pivot