A point (x,y)(x, y)(x,y) is transformed by matrix (0110)\begin{pmatrix} 0 & 1 \\ 1 & 0 \end{pmatrix}(0110). This corresponds to:
Reflection across y=xy = xy=x
Reflection across y=−xy = -xy=−x
Rotation by 90∘90^{\circ}90∘
Reflection across the x-axis