60 setxunit
2.5 setborder
90 setangle_repere
-1.5 1.5 setxrange
-1.5 1.5 setyrange
1 1 settkstep
.5 .5 setsubtkstep
1 1 setmkstep
ticks
subticks
marks
traceaxes
axesarrow
.75 setlinewidth
continu
noir
/X {settvar
    t Cos 3 exp
} def
/Y {settvar
    t Sin 3 exp
} def
  0  2 pi mul {X} {Y} Courbeparam