/usegeomD {} def
/o {0 0 0} def

/Defpoint {defcercle} def

%% syntaxe : A A' Vecteur
/Vecteur {
6 dict begin
   /z' exch def
   /y' exch def
   /x' exch def
   /z exch def
   /y exch def
   /x exch def
   x' x sub
   y' y sub
   z' z sub
end
} def

%% syntaxe u v Addv --> u+v
/Addv {
6 dict begin
   /z' exch def
   /y' exch def
   /x' exch def
   /z exch def
   /y exch def
   /x exch def
   x' x add
   y' y add
   z' z add
end
} def

%% syntaxe : v alpha Mulv --> alpha u
/Mulv {
4 dict begin
   /alpha exch def
   /z exch def
   /y exch def
   /x exch def
   alpha x mul
   alpha y mul
   alpha z mul
end
} def

%% syntaxe : v Norme --> |u|
/Norme {
3 dict begin
   /z exch def
   /y exch def
   /x exch def
   x dup mul
   y dup mul add
   z dup mul add
   sqrt
end
} def

/Milieu {
6 dict begin
   /z' exch def
   /y' exch def
   /x' exch def
   /z exch def
   /y exch def
   /x exch def
   x' x add 2 div
   y' y add 2 div
   z' z add 2 div
end
} def

 /angle_I -135 def
 /angle_J -5 def
 /coeff_vect_I 1 def
 /coeff_vect_J 1 def

/vect_I {angle_I cos angle_I sin coeff_vect_I mulv} def
/vect_J {angle_J cos angle_J sin coeff_vect_J mulv} def
/vect_K {0 1} def

/xyz2xy {
3 dict begin
   /z exch def
   /y exch def
   /x exch def
   vect_I x mulv
   vect_J y mulv
   vect_K z mulv
   addv addv
end
} def

/projxy {
   pop 0
} def

/projxz {
3 dict begin
   /z exch def
   /y exch def
   /x exch def
   x 0 z
end
} def

/projyz {
3 dict begin
   /z exch def
   /y exch def
   /x exch def
   0 y z
end
} def

/projOy {
3 dict begin
   /z exch def
   /y exch def
   /x exch def
   0 y 0
end
} def

/projOx {
3 dict begin
   /z exch def
   /y exch def
   /x exch def
   x 0 0
end
} def

/projOz {
3 dict begin
   /z exch def
   /y exch def
   /x exch def
   0  0 z
end
} def

/Xtick {
1 dict begin
   /x exch def
   [x -.1 0 x .1 0] {xyz2xy} capply ligne
end
} def

/Ytick {
1 dict begin
   /y exch def
   [-.1 y 0 .1 y 0] {xyz2xy} capply ligne
end
} def

/Ztick {
1 dict begin
   /z exch def
   [0 -.1 z 0 .1 z] {xyz2xy} capply ligne
end
} def

/arrowscale {.5 dup} def

/OXarrow {
gsave
   IM stranslate
   O I angle rotate
   arrow
grestore
} def

/OYarrow {
gsave
   JM stranslate
   O J angle rotate
   arrow
grestore
} def

/OZarrow {
gsave
   KM stranslate
   O K angle rotate
   arrow
grestore
} def

/Xmark {
gsave
1 dict begin
   /t exch def
   t Xtick
   setCourrier
   t ch cvs t 0 0 xyz2xy (-2 1) bltext
end
grestore
} def

/Ymark {
gsave
1 dict begin
   /t exch def
   t Ytick
   setCourrier
   t ch cvs 0 t 0 xyz2xy urtext
end
grestore
} def

/Zmark {
gsave
1 dict begin
   /t exch def
   t Ztick
   setCourrier
   t ch cvs 0 0 t xyz2xy (-2 0) bltext
end
grestore
} def


/largeur_repere 5 def
/Longueur_repere 10 def

/Tracerepere1 {
18 dict begin
gsave
   /i {1 0 0} def
   /j {0 1 0} def
   /k {0 0 1} def
   /a {-1 -1 0} def 
   /b {-1 Longueur_repere 0} def 
   /c {largeur_repere Longueur_repere 0} def 
   /d {largeur_repere -1 0} def 
   
   [/I /J /K /A /B /C /D] 
   [i j k a b c d] {xyz2xy} capply
   mapnp

   O I A B interdroite O 1.2 hompoint /Im defpoint
   O I C D interdroite O 1.2 hompoint /IM defpoint
   O J A D interdroite O 1.2 hompoint /Jm defpoint
   O J C B interdroite O 1.1 hompoint /JM defpoint
   /KM {0 ymax} def
   -2 O K ydpoint /Km defpoint
   
   2 setlinewidth
   [B C D] ligne
   .8 setlinewidth
   [B A D] ligne
   
   1 setlinewidth
   [Im IM] ligne
   [Jm JM] ligne
   [O KM] ligne
   
   OXarrow
   OYarrow
   OZarrow
   
   .8 setlinewidth
   gsave
      pointilles
      [Km O] ligne
   grestore
   
   [1] 
   dup {Xtick} apply
   {Xmark} apply
   [1] 
   dup {Ytick} apply
   {Ymark} apply
   [1] 
   dup {Ztick} apply
   {Zmark} apply

   setTimesItalic
      (x) IM (5 0) brtext
      (y) JM (0 -2) dltext
      (z) KM drtext
grestore
end
} def