\left\{ {\left[ {\begin{array}{*{20}c}
 1 & 0 \\
 0 & 0 \\

 \end{array} } \right],\left[ {\begin{array}{*{20}c}
 0 & 1 \\
 0 & 0 \\

 \end{array} } \right],\left[ {\begin{array}{*{20}c}
 0 & 0 \\
 1 & 0 \\

 \end{array} } \right],\left[ {\begin{array}{*{20}c}
 0 & 0 \\
 0 & 1 \\

 \end{array} } \right]} \right\}