>
  <li><code>OT Offset</code> : Amount of harmonic shift.</li>
  <li><code>OT Modulo</code> : Modulo of the harmonic value calculated
  from <code>OT +</code> and <code>OT *</code>.</li>
  <li><code>OT Random</code> : Harmonics randomization amount for each
  note-on.</li>
  </ul>
  <p>Setting <code>OT +</code> and <code>OT Offset</code> as non-integer
  value makes the resulting sound close to some percussion.</p>
  <p><code>OT *</code> and <code>OT Modulo</code> creates unnatural
  harmonics.</p>
  <p>Fo