-4 4 setxrange 
-5 5 setyrange 
 
/X {settvar 
    3 t Cos mul 3 t mul Cos sub 
} def 
/Y {settvar 
    3 t Sin mul 3 t mul Sin sub 
} def 
 
1.5 setlinewidth 
continu 
 
/dessin { 
   gsave 
      tracerepere 
      marks 
      bleu 
      {X} {Y} courbeparam 
   grestore 
} def 
 
{dessin} relief