t</code> is modulo of <code>Interval</code> index.</p>
  <p>For example, considier the following values are set to
  <code>Interval</code>.</p>
  <pre><code>1, 2, 3, 4</code></pre>
  <p>The value of <code>Pitch *</code> multiplies each
  <code>Interval</code>. Now we consider the value of
  <code>Pitch *</code> is set to 0.1. The values change to the
  following.</p>
  <pre><code>0.1, 0.2, 0.3, 0.4</code></pre>
  <p>The above values turns into a sequence. The sequence starts from
  index 0, and increases 1 