25 setxunit
7.5 setborder
-6 6 setxrange
-6 6 setyrange
jpegmode
/a 3 def
/b 8 def
/c 5 def

2 2 settkstep
1 1 setsubtkstep
2 2 setmkstep
ticks
traceaxes
axesarrow
0.75 setlinewidth
continu
bleu
/X {settvar
#rpn#   a * Cos (t)
} def
/Y {settvar
#rpn#   b*(1-cos(t))*Sin (t)
} def
 0 15 pi mul  {X} {Y} Courbeparam