\begin{bmatrix}
 1 &  0 & -1 & -1 &  0 &  0 \\
-1 &  1 &  0 &  0 &  0 &  0 \\
 1 & -1 &  0 &  0 &  0 &  0 \\
-1 &  0 &  0 &  0 &  0 &  0 \\
 0 &  0 &  1 &  0 &  0 &  0 \\
 0 &  0 &  0 &  1 &  0 &  0 \\
 0 & -1 &  0 &  0 &  0 &  0 \\
 0 &  1 &  0 &  0 &  0 &  0 \\
 0 &  0 &  0 &  0 & -1 &  0 \\
 0 &  0 &  0 &  0 &  1 & -1 \\
 0 &  0 &  0 &  0 &  0 &  1
\end{bmatrix}