-1 1 setyrange -2 5 setxrange 250 setwidth .5 dup setquadrillagestep quadrillage /A {2 0} def /B {3.5 0} def /M {A A B vecteur -2 mulv addv} def /N {A A B vecteur 1 3 div mulv addv} def [M N A B] points setTimesItalic (A) A dctext (B) B dctext (M) M dctext (N) N dctext