title: TrueType Font's glyph are made of quadratic Bezier. Why do more than one consecutive off-curve points appear in glyph outline?
body: <p>I'm writing a TTF parser. For a better understanding of the TTF format, I used TTX to extract the ".notdef" glyph data of C:\Windows\calibri.ttf as follow.</p>
  
  <pre><code>&lt;TTGlyph name=".notdef" xMin="0" yMin="-397" xMax="978" yMax="1294"&gt;
        &lt;contour&gt;
          &lt;pt x="978" y="1294" on="1"/&gt;
          &lt;pt x="978" y="0" on="1"/&gt;
          &lt;pt x="44" y="0" on="1"/&gt;
          &lt;pt x="44" y="1294" on="1"/&gt;
        &lt;/contour&gt;
        &lt;contour&gt;
          &lt;pt x="891" y="81" on="1"/&gt;
          &lt;pt x="891" y="1213" on="1"/&gt;
          &lt;pt x="129" y="1213" on="1"/&gt;
          &lt;pt x="129" y="81" on="1"/&gt;
        &lt;/contour&gt;
        &lt;contour&gt;
          &lt;pt x="767" y="855" on="1"/&gt;
          &lt;pt x="767" y="796" on="0"/&gt;
          &lt;pt x="732" y="704" on="0"/&gt;
          &lt;pt x="669" y="641" on="0"/&gt;
          &lt;pt x="583" y="605" on="0"/&gt;
          &lt;pt x="532" y="602" on="1"/&gt;
          &lt;pt x="527" y="450" on="1"/&gt;
          many more points
       &lt;/contour&gt;
       ...some other xml
  &lt;/TTGlyph&gt;
  </code></pre>
  
  <p>You can see more than one off-curve control points in a row. But I've learned that TrueType Font are made of Quadratic Beziers, each of which has two on-curve points (end points) and only one off-curve point (control point). How to interpret these consecutive off-curve points?</p>