+---------------------------------------------------------------+
 100 |---------------------------------------------------------------| H
     |                                                               | a
  50 |                                                               | p
     |                                                               | p
   0 |                                                               | i
     |                                                               | n
 -50 |                                                               | e
     |                                                               | s
-100 |                                                               | s
     +---------------------------------------------------------------+
                                   Time