Please type elements for a 3 x 4 matrix:

Please type elements for a 2 x 2 matrix:

   13   14
   15   16
Composite matrix:

    1    2    3    4    0    0
    5    6    7    8    0    0
    9   10   11   12    0    0
    0    0    0    0   13   14
    0    0    0    0   15   16