This triptych poem can be read in multiple ways; in a sense, it is six smaller poems woven together to make a whole. It can therefore be read vertically (discussing three objects: wood, stone, and water) as well as horizontally (discussing three times: dawn, noonday heat, and an afternoon rain storm).
Additionally, each stanza is linked together by rhyming the middle line with the first and third lines of the subsequent stanza (a version of terza rima). This pattern is used both vertically and horizontally in this poem and therefore, in order to be read as the author intends, the horizontal organization is by stanza rather than by line.