/N 61 def
/k 21 def

1 setlinewidth

%% on genere un polygone regulier a N sommets
/les_points O 5.5 N 0 genpolyreg def

%% on relie le point d'indice i au point d'indice k+i (mod N)
/i 0 def
N {
   les_points i getp 
   les_points i k add N mod getp
   1 trait
   /i i 1 add store
} repeat

%% /str 20 string def
%% setTimesItalic
%%    (n) xmax xmin 2 mul 3 div add .5 sub ymin text
%% setTimes
%%    ( = ) show
%%    N str cvs show
%% setTimesItalic
%%    (k) xmax xmin 4 mul 3 div add .5 sub ymin text
%% setTimes
%%    ( = ) show
%%    k str cvs show