\PGset[0.8em]
\begin{picture}(11,12)

% 10x10
\drawline(1,1)(11,1)    % AE
\drawline(3.2,5)(9.2,5) % BF

\drawline(3.2,5)(1,1)     % BA
\drawline(5.5,5)(4.833,1) % DC
\drawline(9.2,5)(11,1)    % FE

\dashline[80]{0.2}(6.5,11)(3.2,5) % OB
\dashline[80]{0.2}(6.5,11)(5.5,5) % OD
\dashline[80]{0.2}(6.5,11)(9.2,5) % OF



\put( 0.7,  0.2 ){$\scriptstyle A$}
\put( 2.4,  4.7 ){$\scriptstyle B$}
\put( 4.4,  0.2 ){$\scriptstyle C$}
\put( 5.6,  5.1 ){$\scriptstyle D$}
\put(10.3,  0.2 ){$\scriptstyle E$}
\put( 9.4,  4.7 ){$\scriptstyle F$}
\put( 6.3, 11.2 ){$\scriptstyle O$}


\end{picture}
\PGrestore