Echelon Matrix/Examples/Arbitrary Example 4

Example of Echelon Matrix

 * $\begin {bmatrix}

1 & 0 & 2 & 0 \\ 0 & 0 & 0 & 0 \\ 0 & 1 & 0 & 2 \\ \end {bmatrix} $ is not an echelon matrix, because row $2$ is a zero row, coming before row $3$.