25 setxunit 7.5 setborder 90 setangle_repere -5 7 setxrange -5 7 setyrange /quadrillagegray 0.4 def 1 setquadrillagexstep 1 setquadrillageystep quadrillage 1 1 settkstep .5 .5 setsubtkstep 2 2 setmkstep ticks subticks marks traceaxes axesarrow unites