I think that I shall never see A graph more lovely than a tree. A tree whose cru...

  I think that I shall never see
  A graph more lovely than a tree.
  A tree whose crucial property
  Is loop-free connectivity.
  A tree that must be sure to span
  So packets can reach every LAN.
  First, the root must be selected.
  By ID, it is elected.
  Least-cost paths from root are traced.
  In the tree, these paths are placed.
  A mesh is made by folks like me,
  Then bridges find a spanning tree.

Radia Perlman, 'Algoryhme' https://web.archive.org/web/20110609192559/http://www.csua.b...

  I hope that we shall one day see
  A graph more lovely than a tree.
  A graph to boost efficiency
  While still configuration-free.
  A network where RBridges can
  Route packets to their target LAN.
  The paths they find, to our elation,
  Are least cost paths to destination!
  With packet hop counts we now see,
  The network need not be loop-free!
  RBridges work transparently,
  Without a common spanning tree.

Radia Perlman in apparent alias as Ray Perlner, 'Algorhyme V2' RFC6325 https://tools.ietf.org/html/rfc6325#section-1.1