\begin{tikzpicture}[scale=0.9] % \draw[step=1cm, gray, very thin] (-5,-5) grid (5,5); \draw[thick] (160:5)coordinate(M1) -- (-20:5)coordinate(M2) -- (20:5)coordinate(M3) -- (195:6)coordinate(M4) -- (165:6)coordinate(M5) -- (-14:6)coordinate(M6) -- (14:6)coordinate(M7) -- (190:7)coordinate(M8) -- (170:7)coordinate(M9) -- (-8.9:7)coordinate(M10) -- (8.9:7)coordinate(M11) -- (186:8)coordinate(M12); \draw[thick, {-latex}] (M1) -- +(0,-4)node[right]{Output}; \draw[thick, {latex-}] (M12) -- +(0,3)node[right]{Input}; \mirror[angle=125] at (M1); \mirror[angle=125-180] at (M2); \mirror[angle=55] at (M3); \mirror[angle=55+180] at (M4); \mirror[angle=125] at (M5); \mirror[angle=125-180] at (M6); \mirror[angle=55] at (M7); \mirror[angle=55+180] at (M8); \mirror[angle=125] at (M9); \mirror[angle=125-180] at (M10); \mirror[angle=55] at (M11); \mirror[angle=55+180] at (M12); \filldraw[fill=red!60!black, fill opacity=0.7, draw=black, thick] (-.52,-.1) rectangle ++(.25,.4); \node at (-0.4,-0.8){laser medium}; \end{tikzpicture}