%% d'apres un code original de Maxime Chupin et Manuel Luque

-2 2 setxrange
-2 2 setyrange
100 setxunit

60 60 12 SetCamPos
0 0 0 SetCamView
%/ScreenDist .075 def

-10 10 setxrange3d
-3 3 setyrange3d
2 setlinejoin

.1 setlinewidth
gris

/g {
3 dict begin
   /t exch def
#rpn# 0.5*Sin(0.707)*t*Cos(t)
#rpn# 0.5*Sin(0.707)*t*Sin(t)
#rpn# -0.5*t*Cos(0.707)
end
} def

/g' { % derivee premiere
3 dict begin
   /t exch def
0.5 0.707 Sin mul t Cos t t Sin mul sub mul %  0.5*Sin(0.707)*(Cos(t)-t*Sin(t))
0.5 0.707 Sin mul t Sin t t Cos mul add mul %  0.5*Sin(0.707)*(Sin(t)+t*Cos(t))
-0.5 0.707 Sin mul          		    % -0.5*Sin(0.707)
end
} def

/g'' { % derivee seconde
3 dict begin
   /t exch def
-0.5 0.707 Sin mul t mul t Cos mul %  -0.5*Sin(0.707)*t*Cos(t)
0.5 0.707 Sin mul t Cos 2 mul t t Sin mul sub mul   %  0.5*Sin(0.707)*(2*Cos(t)-t*Sin(t))
0          %   0
end
} def

% spirale 
% t_min t_max rayon_tube [resolution]
-25.4 25.4 (g) .4 [1000 10] newtube
dup [.5 .6] solidputhuecolors

%Cone1 
-10 8.543256973 0 [36 72] newconecreux
dup (.5 setfillopacity jaune) (.5 setfillopacity jaune) inoutputcolors
 
%Cone2
10 8.543256973 0 [36 72] newconecreux
dup (.5 setfillopacity jaune) (.5 setfillopacity jaune) inoutputcolors

solidfuz
solidfuz
drawsolid**