diagonally reflect a matrix
<p>I'm not sure if this question has been either asked
or quite possibly already answered. If I start with
an original 3x3 matrix:</p>

<pre>
    1 2 3
    4 5 6
    7 8 9
</pre>

<p>, how would I produce the following 3x3 matrix:</p>

<pre>
    9 6 3
    8 5 2
    7 4 1 
</pre>

<p>??</p>
