<slide>
<title>Variables</title>
<blurb fontsize="3.5em">
PHP uses reference counting to manage base types.
</blurb>
<example filename="referencecounting.php" />
<blurb fontsize="3.5em">
To avoid copy-on-write, you would use the alias operator (%&amp;%).
</blurb>
<example filename="alias.php" />
</slide>
