\begin{tikzpicture}[
squarednode/.style={rectangle, draw=black!20, fill=white!5, very thick, minimum size=1cm},
    squarednodeG/.style={rectangle, draw=black!20, fill=green!20, very thick, minimum size=1cm},
    squarednodeY/.style={rectangle, draw=black!20, fill=yellow!20, very thick, minimum size=1cm},
    ]
    
    \node[squarednode] at (0.5,0.5) (int) {1};
    \node[squarednode] at (1.5,0.5) (int) {3};
    \node[squarednode] at (2*1.75,0.5) (int) {6};
    \node[squarednode] at (2*2.25,0.5) (int) {7};
    \node[squarednode] at (2*2.75,0.5) (int) {8};
    \node[squarednode] at (0.5,1.5) (int) {2};
    \node[squarednode] at (1.5,1.5) (int) {5};
    \node[squarednode] at (2.5,0.5) (int) {4};
    \draw[] (0,0) -- (6,0)--(6,1)-- (2,1)--(2,2)--(0,2)--cycle;
    
    \end{tikzpicture}