intro

  [------8-7-7-7------8-7-7-7----8-7-7-7--7-8-5----------------------]
  [-0-7-7--------0-7-7-----0-7-7-------------------------------------]
  [------------------------------------------------------------------]
  [------------------------------------------------------------------]
  [------------------------------------------------------------------]
  [------------------------------------------------------------------]

ending
  [-------8-7-7-7-8--7-8-5---8-7-7-7--7-8-5--------------------------]
  [-0-7-7-----------------7-7----------------------------------------]
  [------------------------------------------------------------------]
  [------------------------------------------------------------------]
  [------------------------------------------------------------------]
  [------------------------------------------------------------------]