title: Are there any B-tree programs or sites that show visually how a B-tree works
body: <p>I found this website that lets you insert and delete items from a B-tree and shows you visually what the B-tree looks like:</p>
  
  <p><a href="http://slady.net/java/bt/view.php" rel="noreferrer">java b-tree</a></p>
  
  <p>I'm looking for another website or program similar to this.  This site does not allow you to specify a B-tree of order 4 (4 pointers and 3 elements), it only lets you specify B-trees with an even number of elements.  Also, if possible, I'd like to be able to insert letters instead of numbers.</p>
  
  <p>I think I actually found a different site but that was a while ago and can't find it anymore.</p>