/**
  \example timer2.cpp 

  This sketch configures a timer to count like a wall clock, and
  perform an event every twelve hours.  (It's a little hard to imagine
  why we couldn't use an alarm for this; we'll pretend it really needs
  to be an \e extremely \e accurate twelve hours.)

  We saw that a timer is specified by two parameters: Its 'tick speed'
  in microseconds per tick, and how many ticks before it 'laps' or
  returns to zero.

  A regular clock, for example, might tick once per second, and lap
  after twelve hours -- or in terms the begin() method understands:
  Tick once per 1,000,000 microseconds, and lap after 60*60*12 ticks.

 */
