ariables differently to ours. They do not store a copy of a value in the environment, but actually a pointer, or reference, to it directly. Because pointers are used, rather than copies, just like in C, there is much less overhead required when using large data structures.</p>

<div class='pull-left alert alert-warning' style="margin: 15px; text-align: center;">
  <img src="/static/img/garbage.png" alt="garbage" class="img-responsive" width="249px" height="289px"/>
  <p><small>Garbage Collection &bull; 