title: Why summation top and bottom ⎲⎳?
body: <p>I totally understand the necessity of integral, and brackets by pieces (<code>2320</code> <code>2321</code> <code>239B</code>-<code>23AE</code>) Since it helps building large notations. </p>
  
  <p>But the for the large summation <code>23B3</code> <code>23B4</code>, if one stretch these two, they will still lose their shapes. I do not understand <strong>what</strong> is the logic behind separating this character, or <strong>why</strong> not a corresponding one for the product symbol <code>220F</code>. Furthermore, I wonder in <strong>which</strong> case these two symbols should be used.</p>