\begin{tikzpicture}[framed, scale = 0.55, every node/.style={scale=0.6}]
    %tri after movement
    \draw[
        fill,
        lightgray
    ] (-0.3,0) -- (6.3,0) -- (3,3.3) -- cycle;

    %primary tri
    \draw[
        fill,
        gray
    ] (0,0) -- (6,0) -- (3,3) -- cycle;

    %arrow
    \draw[
        -to,
        line width = 1.2pt,
        black
    ] (3,3) -- (3,4);

    % occlusion tri
    \draw[
        fill,
        red
    ] (3,2) -- (4.5,0.2) -- (6,3);

    % samples
    \foreach \x/\y in {
            1/0.5,
            1/2.5,
            3/0.5,
            3/2.5,
            5/0.5,
            5/2.5
        }
    \node[fill = yellow] at (\x,\y) {};
\end{tikzpicture}