1. Write a command that replaces the entries in the first two rows and first two columns of the input
matrix with zeros. The input matrix will need to be at least 2x2.
2. Write a command that takes two matrices of sizes, $m \times n$ and $l \times p$ and constructs a matrix of size
$(m+l) \times (n+p)$, with the first matrix in the upper left hand corner, and the second matrix in the lower right
hand corner. All the entries in the upper right hand corner should be zeros, and all the entries in the lower
left hand corner should be ones. Hint: you will need to use the size, zeros, and ones commands if you
want to do this efficiently, but other methods are possible.