number <code class="code">o2</code>. It works correctly even if
   <code class="code">v1</code> and <code class="code">v2</code> are the same array, and the source and
   destination chunks overlap.
<p>

   Raise <code class="code"><span class="constructor">Invalid_argument</span> <span class="string">"Array.blit"</span></code> if <code class="code">o1</code> and <code class="code">len</code> do not
   designate a valid subarray of <code class="code">v1</code>, or if <code class="code">o2</code> and <code c