Cezanne siad, " There are
          no straight lines in nature "

       Philippe Petit might disagree,
        ------------------/--------------------

      Robert Bruce, a vertical thinker
         failed to invent the Yo-Yo ®.

       Heaney wrote The Spirit Level,
        no doubt referring to alcohol.

     But wait, being Irish, he may have
      meant a construction implement!

       Mind you, despite the bubble, it
        does have a percentage proof.

         I'm not sure about Cezanne
         and if Galileo was a builder,

      He would have recognized the
      spider was a perfect pendulum

     And the plumb bob, as we know it
      today, could have had eight legs