  A pump as a Markov chain. One step is one hour.

  from      | on            | to
  ----------+---------------+---------
  Off       | 0.7           | Off
  Off       | 0.3           | On
  On        | 0.4           | Off
  On        | 0.58          | On
  On        | 0.02          | Faulted
  Faulted   | 0.1 repaired  | Off
  Faulted   | 0.9           | Faulted

  The numbers leaving each state sum to one: Off 0.7 + 0.3,
  On 0.4 + 0.58 + 0.02, Faulted 0.1 + 0.9.
