On Monday, when the sun is hot
      I wonder to myself a lot:
      "Now is it true, or is it not,
      That what is which and which is what?"

      On Tuesday, when it hails and snows,
      The feeling on me grows and grows
      That hardly anybody knows,
      If those are these or these are those.

      On Wednesday, when the sky is blue,
      And I have nothing else to do,
      I sometimes wonder if it's true
      That who is what and what is who.

      On Thursday, when it starts to freeze
      And hoar-frost twinkles on the trees,
      How very readily one sees
      That these are whose - but whose are these?
 

A.A. Milne - Kanga and Baby Roo "Winnie-The-Pooh"