The hypotenuse of an isosceles triangle

Detroit poet, Philip Levine, has been selected as the new Poet Laureate of the United States. Selected by the librarian of Congress (James Billington), Levine follows poet W. S. Merwin in the honored position.  A Poet Laureate is responsible merely for giving readings in October and May but some laureates also use the position to proselytize for poetry.   Here, from Levine's early collection, What Work Is (Knopf, 1992), is a poem that looks back on a math-art moment in a middle-school classroom.