% TeX root = ../main.tex

\begin{tikzpicture}[scale=0.5]
    \begin{axis}[
        axis lines = center,
        axis on top,
        xmin=0,
        xmax=6.3,
        ymin=0,
        ymax=5.3,
        y=1cm,
        x=1cm,
        ytick={0,...,5},
        xtick={0,...,6},
        xlabel = x,
        ylabel = y,
        font=\tiny
    ]
        % Box
        \addplot[mark=none,draw=black,fill=rwth-50] coordinates {(1,2) (1,4) (5,4) (5,2)} -- cycle;
        % Intervals
        \addplot[mark=none,dashed] coordinates {(1,0) (1,2)};
        \addplot[mark=none,dashed] coordinates {(5,0) (5,2)};
        \addplot[mark=none,dashed] coordinates {(0,2) (1,2)};
        \addplot[mark=none,dashed] coordinates {(0,4) (1,4)};
        % Points
        \addplot[only marks,mark=o] coordinates {
            (1,4) (2,4) (3,4) (4,4) (5,4)
            (1,3) (2,3) (3,3) (4,3) (5,3)
            (1,2) (2,2) (3,2) (4,2) (5,2)
        };
    \end{axis} 
\end{tikzpicture}