Given the state-space representation of the system model, construct the appropriate block diagram, and directly use it to find the transfer matrix.

\(\left\{\begin{array}{l}\dot{\mathbf{x}}=\mathbf{A} \mathbf{x}+\mathbf{B} u \\ y=\mathbf{C x}+D u\end{array}\right.\)
where \[\mathbf{x}=\left\{\begin{array}{l}
x_{1} \\
x_{2} \\
x_{3}
\end{array}\right\}, \mathbf{A}=\left[\begin{array}{ccc}
0 & 1 & 0 \\
0 & 0 & 1 \\
-\frac{1}{2} & -1 & -\frac{1}{2}
\end{array}\right], \mathbf{B}=\left[\begin{array}{l}
0 \\
0 \\
1 \end{array}\right], \quad \mathbf{C}=\left[\begin{array}{lll}
1 & 2 & 0 \end{array}\right], D=0, u=u\]