Summing thin slices

This poem by recent (2008-2010) poet laureate Kay Ryan at first made me think of calculus, of integration, summing all the thin slices to find the area under a curve.  And then the poem moved me on. 

Integrals -- a poem

Integrals    by Jonathan Holden

     Erect, arched in disdain,
the integrals drift from left
across white windless pages
to the right,
serene as swans.