%% PhS
%% 

40 setxunit
-6 7  setxrange
-8 6 setyrange




%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% procédures
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%



/dtA {
2 dict begin %% Ax Ay
	/Ay exch def
	/Ax exch def
	1 Ax Ay norme div arctan
end
	} def




/alpha_A {
4 dict begin %% Th Ax Ay
	/Ay exch def
	/Ax exch def
	/Th exch def
	/Th0 Ax Ax Ay norme div arccos 
	   Ay 0 le {-1 mul} if
	      def
	Th Th0 sub
	Ax Ay dtA abs div 
	1 min -1 max 90 mul
end
	} def


/U_alpha {
1 dict begin  %% alpha
	/alpha exch def
	alpha cos alpha sin
end
	} def




/V_A {
5 dict begin  %% Th Ax Ay
	/Ay exch def
	/Ax exch def
	/Th exch def
	/Th0 Ax Ax Ay norme div arccos 
	   Ay 0 le {-1 mul} if
	      def
	/al_Th Th Ax Ay alpha_A def
	al_Th Th0 add U_alpha
	Rayon Ax Ay norme sub 0 max
	al_Th cos dup mul mul mulv
end
	} def



/M_Th {
1 dict begin   %% Th
	/Th exch def
	Th cos Rayon mul
	Th sin Rayon 0.7 mul  mul
	Th 1 1 V_A addv
	Th -0.5 -1 V_A addv
	Th 0 -2 V_A addv
	Th -2.5 2 V_A addv
	Th 3 5 V_A addv
	Th 2.8 -3 V_A addv
end
	} def




/M_Th_x {
1 dict begin   %% Th
	/Th exch def
	Th M_Th pop
end
	} def

/M_Th_y {
1 dict begin   %% Th
	/Th exch def
	Th M_Th exch pop
end
	} def


/Grad_M {
2 dict begin  %% Th long
	/long exch def
	/Th exch def
	Th  M_Th Th 0.1 add M_Th vecteur
	0.1 1 exch div mulv
	%% dupp norme long exch div mulv
	10 mulv
	exch -1 mul
end
	} def




%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% definition d'une couleur
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

/coul1 {120 255 div 70 255 div 9 255 div setrgbcolor} def



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% tracés
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
1.3 setlinewidth
/arrowscale {1.3 dup} def
continu
0 0 point



coul1
-180 185 settrange

500 setresolution
1 1 5 {
	coul1
	/Rayon exch def
	{M_Th_x} {M_Th_y} courbeparam
	orange
	-180 20 160 {
	1 dict begin
		/a exch def
		[a M_Th dupp a 1 Grad_M addv] ( ->) ligne
end
	} for

} for




-180 20 160 {
1 dict begin
	/a exch def
	[a M_Th dupp a 1 Grad_M addv] ( ->) ligne
end
	} for



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% texte
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