risk of losing, or winning. Walkers (molecules, drunks...) moving left
          or right of a centre line are another common example.
        </p>
<p>
          The random variate <span class="emphasis"><em>x</em></span> is the fraction of time spent
          on the 'winning' side. If half the time is spent on the 'winning' side
          (and so the other half on the 'losing' side) then <span class="emphasis"><em>x = 1/2</em></span>.
        </p>
<p>
          For large numbers of tosses, this is modelle