Here is why: <a href="http:&#x2F;&#x2F;pastebin.com&#x2F;t3Q3CW4j" rel="nofollow">http:&#x2F;&#x2F;pastebin.com&#x2F;t3Q3CW4j</a><p>This is particularly infuriating because the proper way to handle bound variables is already known: <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;De_Bruijn_index" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;De_Bruijn_index</a> .