% --- start of displayed preamble in the book --- input geometriesyr16 % --- end of displayed preamble in the book --- defaultfont:="ptmr8r"; warningcheck:=0; beginfig(1) figuremainlevee(0,0,5u,5u); trace grille(1) withcolor gris; origine((3,2)); trace axes; pair A,B,C; A=placepoint(-2,-1); B=placepoint(1,-1); C=placepoint(1,2); trace polygone(A,B,C) withcolor rouge; trace cercles(A,B,C) withcolor bleu; nomme.llft(A); nomme.lrt(B); nomme.top(C); finmainlevee; endfig; end;