(2) Vectors $\overrightarrow{O A}=(1,0), \overrightarrow{O B}=(1,1), O$ is the origin, and a moving point $P(x, y)$ satisfies $\left\{\begin{array}{l}0 \leqslant \overrightarrow{O P} \cdot \overrightarrow{O A} \leqslant 1, \\ 0 \leqslant \overrightarrow{O P} \cdot \overrightarrow{O B} \leqslant 2,\end{array}\right.$ then the area of the figure formed by point $Q(x+y, y)$ is . $\qquad$
(2) 2 Hint: From the problem, the point $P(x, y)$ satisfies $\left\{\begin{array}{l}0 \leqslant x \leqslant 1, \\ 0 \leqslant x+y \leqslant 2,\end{array}\right.$ Let $\left\{\begin{array}{l}x+y=u, \\ y=v,\end{array}\right.$ then the point $Q(u, v)$ satisfies $\left\{\begin{array}{l}0 \leqslant u-v \leqslant 1, \\ 0 \leqslant u \leqslant 2,\end{array}\right.$ Draw the plane region formed by the point $Q(u, v)$ in the $u O v$ plane, as shown in the shaded area in the figure, its area equals 2.