\def\Symbol{{\tt {\char'134}symbol}} \vbox{\line{\hfil \diagram{\xaxis3truecm,0.,1.0,0.5,;\noscale \yaxis4truecm,-1.0,9.0,1.,\Symbol;\nogrid} {\values{ \symbol0\point0.5,0.0; \symbol1\point0.5,1.0; \symbol2\point0.5,2.0; \symbol3\point0.5,3.0; \symbol4\point0.5,4.0; \symbol5\point0.5,5.0; \symbol6\point0.5,6.0; \symbol7\point0.5,7.0; \symbol8\point0.5,8.0; \symbol9\point0.5,9.0;}} \hfil \diagram{\xaxis3truecm,0.,1.0,0.5,;\noscale \yaxis4truecm,-1.0,9.0,1.,;} {\values{ \symbol0\point0.5,0.0; \symbol1\point0.5,1.0; \symbol2\point0.5,2.0; \symbol3\point0.5,3.0; \symbol4\point0.5,4.0; \symbol5\point0.5,5.0; \symbol6\point0.5,6.0; \symbol7\point0.5,7.0; \symbol8\point0.5,8.0; \symbol9\point0.5,9.0;}} \hfil} \vskip -\medskipamount \noindent{\bf Figure~13. \rm Ten symbols are predefined: \printsymbol0 = \Symbol{\tt0}, \printsymbol1 = \Symbol{\tt1}, \dots, \printsymbol9 = \Symbol{\tt9}.}}