Consider three file systems, called
<literal>A
</literal>,
<literal>B
</literal>, and
<literal>C
</literal>. Each file system has one root directory, which contains two other directories, called
<literal>A1
</literal>,
<literal>A2
</literal> (and likewise
<literal>B1
</literal>,
<literal>B2
</literal> and
<literal>C1
</literal>,
<literal>C2
</literal>).