-2 2 setyrange
-2.5 2.5 setxrange

.5 .5 setquadrillagestep
quadrillage

currentlinewidth 1.5 mul setlinewidth
tracerepere

[1.5 -1.5 .5 -.5 0] {ymark} apply
marks
/f {2.5 mul 1 add Sin 1.5 mul} def

medium setlinewidth
-2 2 (f) Courbe