\begin{bmatrix}
-1 &  -1 &  1 &  0 \\
 2 & 3/2 & -1 &  0 \\
-2 &  -2 &  0 &  1 \\
-1 &   0 &  0 &  0 \\
 0 &  -1 &  0 &  0 \\
 0 &   0 &  0 & -1
\end{bmatrix}