title: How to convert tree-form tuples to matrix-form tuples?
body: <p>Pardon in advance if my question appears too naive or too basic. I'm a still learning to use SE.</p>
  
  <p>Is there a quick way to convert tree-form tuple to a matrix-form tuple (triangular form)?</p>
  
  <p>That is this:</p>
  
  <pre><code>t=((1,),(2,3,),(4,5,6,),(7,8,9,10,))
  </code></pre>
  
  <p>to this:</p>
  
  <pre><code>t=((1,0,0,0,),(2,3,0,0,),(4,5,6,0,),(7,8,9,10,))
  </code></pre>
  
  <p>Just an idea would suffice. I can try implementing it myself.</p>