## Precalculus (6th Edition) Blitzer

The matrix is, $A=\left[ \begin{array}{*{35}{r}} 2 & 2 & 2 \\ 1 & 2 & 1 \\ 1 & 2 & 1 \\ \end{array} \right]$
Consider the rectangular boxes: $\begin{matrix} {{a}_{11}} & {{a}_{12}} & {{a}_{13}} \\ {{a}_{21}} & {{a}_{22}} & {{a}_{23}} \\ {{a}_{31}} & {{a}_{32}} & {{a}_{33}} \\ \end{matrix}$ To form a digital photograph of the letter T with dark gray letters, we color the boxes ${{a}_{11}},{{a}_{12}},{{a}_{13}},{{a}_{22}},{{a}_{32}}$ with dark gray. We use a light gray background for the other boxes, like so: $\begin{matrix} 2 & 2 & 2 \\ 1 & 2 & 1 \\ 1 & 2 & 1 \\ \end{matrix}$ Thus, the required matrix representing the letter is, $A=\left[ \begin{array}{*{35}{r}} 2 & 2 & 2 \\ 1 & 2 & 1 \\ 1 & 2 & 1 \\ \end{array} \right]$.