How to merge four matrices of order 3*3 in to one matrix of order 6*6
<p>I have created two  matrices using Numpy in Python:</p>

<pre><code>mat=np.matrix([[1,0,0],[0,0,1],[0,0,2]])
mat1= np.matrix([[1,0,0],[0,1,0],[0,0,1]])
</code></pre>

<p>I want to merge these two matrices. How can I do that?
The output should be <code>[mat,mat1]</code></p>
