Klein Four-Group/Cayley Table

Cayley Table for Klein $4$-Group
The Klein $4$-group can be described completely by showing its Cayley table:
 * $\begin{array}{c|cccc}

& e & a & b & c \\ \hline e & e & a & b & c \\ a & a & e & c & b \\ b & b & c & e & a \\ c & c & b & a & e \\ \end{array}$