\begin{tikzpicture}[scale=0.9]
  \small
  
  \draw (120pt,0pt) -- ( 200pt,0pt);
  \draw (120pt,0pt) -- ( 160pt,30pt);
  \draw (200pt,0pt) -- ( 160pt,30pt);

  \draw (120pt,0pt) -- ( 120pt,-12pt);
  \draw (200pt,0pt) -- ( 200pt,-12pt);
  \draw (160pt,30pt) -- (160pt,42pt);


  \draw[fill=lightgray] (120pt,0pt) circle (8pt);
  \draw[fill=lightgray] (200pt,0pt) circle (8pt);

  \draw[fill=lightgray] (160pt,30pt) circle (8pt);

  \draw[fill=green] (114pt,-12pt) rectangle (126pt,-24pt);
  \draw[fill=blue] (194pt,-12pt) rectangle (206pt,-24pt);

  \draw[fill=green] (154pt, 42pt) rectangle (166pt,54pt);


\end{tikzpicture}