\begin{figure}[H] \begin{center} \unitlength=4pt \begin{picture}(20, 26)(0,-3) \gasset{Nw=5,Nh=5,Nmr=2.5,curvedepth=0} \thinlines \node(A0)(0,20){$0$} \node(A1)(20,20){$1$} \node(A2)(20,0){$2$} \node(A3)(0,0){$3$} \drawedge(A0,A1){$a$} \drawedge(A1,A2){$a$} \drawedge(A2,A3){$a$} \drawedge(A3,A0){$a$} \drawloop[loopangle=180](A0){$b$} \drawloop[loopangle=0](A1){$b$} \drawloop[loopangle=0](A2){$b$} \drawedge[curvedepth=-4,ELside=r](A3,A0){$b$} \end{picture} \end{center} \caption{L'automate de {\v C}ern{\'y}.} \end{figure} |