% This is a TikZ implementation of the extended Dynkin diagram for the class F4.
% The numbering follows the one used by LiE (http://http://wwwmathlabo.univ-poitiers.fr/~maavl/LiE/).
% The highest root is denoted by \star or \gamma_{\star} and has a different colour.
%
%  You'll need to load the following packages
%% \usepackage{tikz}
%% \usetikzlibrary{calc}   % this is needed in order to be able to do coordinate calculations
%% \usetikzlibrary{topaths}
%% \usetikzlibrary{decorations}
%% \usetikzlibrary{decorations.pathmorphing}
%
% Feel free to use it whereever you like, but please leave my name in the drawing.
% 
% 08/04/2015, P. Meessen 
\begin{center}
   \begin{tikzpicture}[scale=.7]
    %%%%%%%%    08/04/2015, P. Meessen 
    %% draw the background coordinate-grid, clearly not needed when finished
    %\draw[step=.5cm,color=gray] (0,0) node[anchor=north east] {$(0,0)$} grid (15,5) node[anchor=south west] {$(15,5)$};
    %% Draw the part for the highest root
    \draw[color=green!51!blue, line width=1pt, dashed] (0,2) -- (2,2);
    \fill[green!51!blue] (0,2) circle (7pt);
    \draw (0,1.4) node[color=green!51!blue] {$\star$};
    %% Draw the horizontal roots
    \fill[black] (2,2) circle (7pt);
    \fill[black] (4,2) circle (7pt);
    \fill[black] (6,2) circle (7pt);
    \fill[black] (8,2) circle (7pt);
    %% Draw the lines connecting the horizontal roots
   \draw[color=black, line width=1pt] (2,2) -- (4,2);
   \draw[color=black, line width=1pt] (4,2.2) -- (6,2.2);
   \draw[color=black, line width=1pt] (4,1.8) -- (6,1.8);
   \draw[color=black, line width=1pt] (6,2) -- (8,2);
   \draw[color=black, line width=1pt] (4.9,1.6) -- (5.1,2) -- (4.9,2.4);
   %% Put the labels
   \draw (2,1.4) node[color=black] {$1$};
   \draw (4,1.4) node[color=black] {$2$};
   \draw (6,1.4) node[color=black] {$3$};
   \draw (8,1.4) node[color=black] {$4$};
   %% Indicate that this Dynkin diagram is for e_7
   \draw (3,3) node[color=black] {$\mathfrak{f}_{4}$};
   \end{tikzpicture}
\end{center}