% ------------------------------------------------------------------------------
% Copyright (c) 2010, 2020 Contributors to the Eclipse Foundation
%
% See the NOTICE file(s) distributed with this work for additional
% information regarding copyright ownership.
%
% This program and the accompanying materials are made available under the terms
% of the MIT License which is available at https://opensource.org/licenses/MIT
%
% SPDX-License-Identifier: MIT
% ------------------------------------------------------------------------------
{\ttfamily
\begin{tikzpicture}[x=1ex,y=1ex,thin,>=triangle 45,auto]
\path
          node[circle,minimum size= 4ex,draw]    (G){}
++ (60,0) node[circle,minimum size= 4ex,draw]    (H){};
\draw (0,2) -- (60,2);
\draw (0,-2) -- (60,-2);
\draw (12.5,2) rectangle (17.5,7);
\draw (27.5,2) rectangle (32.5,7);
\draw (47.5,2) rectangle (52.5,7);
\draw (50.0,5) node {0};
\draw (30.0,5) node {1};
\draw (15.0,5) node {2};
\draw (15.0,2) -- (15.0,-12);
\draw (30.0,2) -- (30.0,-8);
\draw (50.0,2) -- (50.0,-4);
\draw [help lines](60.0,0) -- (60.0,-2);
\draw (60.0,-2) -- (60.0,-12);
\draw [<->] (50.0,-4) -- (60.0,-4);
\draw (55.0,-4) node [anchor = north] {10.0};
\draw [<->] (30.0,-8) -- (60.0,-8);
\draw (45.0,-8) node [anchor = north] {30.0};
\draw [<->] (15.0,-12) -- (60.0,-12);
\draw (35.0,-12) node [anchor = north] {45.0};
\draw [->] (4,1) -- (10,1);
\draw [->] (40,1) -- (46,1);
\end{tikzpicture}
}