Matrix Stretch Transformation

We can stretch along the $y$-axis and squish along the $x$-axis with the following matrix:

$$\left(\begin{array}{cc}0.5& 0\\ 0& 2\end{array}\right)\cdot \left(\begin{array}{c}x\\ y\end{array}\right)=\left(\begin{array}{c}0.5x\\ 2y\end{array}\right)$$