AB-BA so that you get another matrix I want to find out what the matrices are (a) and (b) so that $ab-ba = $   
$$
\begin {pmatrix} 1 & 0 & 0 & 0 \\ 0 & 1 & 0 & 0 \\ 0 & 0 & -1 & 0 \\ 0 & 0 & 0 & -1 \\
\end {pmatrix} $$
This is the outcome of $ab-ba$ is. Ive been struggling with this for the past hour or so. All matrices have to be $4\times,4$

I like $$ A = \begin{pmatrix} 0 & 0 & 0 & 0 \\ 0 & 0 & 0 & -1 \\ 1 & 0 & 0 & 0 \\ 0 & 0 & 0 & 0 \end{pmatrix} \\
    B = \begin{pmatrix} 0 & 0 & -1 & 0 \\ 0 & 0 & 0 & 0 \\ 0 & 0 & 0 & 0 \\ 0 & -1 & 0 & 0 \end{pmatrix} \text{.} $$
