28 setxunit
7.5 setborder
90 setangle_repere
-3.3 1.6 setxrange
-3 3 setyrange
1 1 settkstep
.5 .5 setsubtkstep
1 1 setmkstep
ticks
subticks
marks
traceaxes
axesarrow
1.75 setlinewidth
continu
bleu
/X {settvar
#rpn#   2*Cos(t) - Cos(2*t)
} def
/Y {settvar
#rpn#   2*Sin(t) + Sin(2*t)
} def
  0 pi 2 mul {X} {Y} Courbeparam
noir
continu
/XX {settvar 
#rpn# Cos(t)
} def
/YY {settvar 
#rpn# Sin(t)
} def
0.75 setlinewidth
 0 2 pi mul {XX} {YY} Courbeparam