diff --git a/GravityField/.gitignore b/GravityField/.gitignore
index dad9484..bd256a5 100644
--- a/GravityField/.gitignore
+++ b/GravityField/.gitignore
@@ -4,6 +4,8 @@ animation
 
 WS/*.pgm
 WS/*.png
+WS/*/*.pgm
+WS/*/*.png
 
 *.gif
 *.log
diff --git a/GravityField/WS/field/README.md b/GravityField/WS/field/README.md
new file mode 100644
index 0000000..1dac8fa
--- /dev/null
+++ b/GravityField/WS/field/README.md
@@ -0,0 +1,2 @@
+
+# placeholder
diff --git a/GravityField/WS/nanim/README.md b/GravityField/WS/nanim/README.md
new file mode 100644
index 0000000..1dac8fa
--- /dev/null
+++ b/GravityField/WS/nanim/README.md
@@ -0,0 +1,2 @@
+
+# placeholder
diff --git a/GravityField/WS/troid/README.md b/GravityField/WS/troid/README.md
new file mode 100644
index 0000000..1dac8fa
--- /dev/null
+++ b/GravityField/WS/troid/README.md
@@ -0,0 +1,2 @@
+
+# placeholder
diff --git a/GravityField/animation.f90 b/GravityField/animation.f90
index a2b502f..a8c7419 100644
--- a/GravityField/animation.f90
+++ b/GravityField/animation.f90
@@ -10,18 +10,81 @@ program animation
   implicit none
 
   ! some configuration constants
-  integer, parameter      :: S_WIDTH  = 800
-  integer, parameter      :: S_HEIGHT = 600
-  integer, parameter      :: NB_BODY  = 20
+  integer, parameter      :: S_WIDTH  = 1024
+  integer, parameter      :: S_HEIGHT = 1024
+  integer, parameter      :: NB_BODY  = 150
 
+  !!! WARNING : global variables !!!
   type(massbody)          :: planets(NB_BODY)
-  integer                 :: foo
-  character(len=100)      :: filename
+  ! integer                 :: foo
 
   call init_random()
-  call create_some_planets(planets, 13.37, 2048, 2048)
+  call create_some_planets(planets, 1337e3, S_WIDTH , S_HEIGHT)
+  call barycentre_bodies(planets)
 
+  call la_grande_boucle(0, 2000, planets)
 
-  STOP ': YOLO TIME'
+  STOP ': YOLO TIME *NOW*'
+
+!-----------------------------------------------------------------------
+contains
+!-
+!         fabrication d'une de la sequence complete
+!-
+subroutine la_grande_boucle(start, nbre, moons)
+  integer, intent(in)            :: start, nbre
+  type(massbody), intent(inout)  :: moons(:)
+
+  character(len=100)      :: filename
+  integer                 :: pass 
+
+  do pass=start, start+nbre-1
+  
+    write (filename, "(a, i5.5, a)") 'WS/nanim/', pass, '.pgm'
+    write(0, *) filename
+
+    call build_and_write_a_field(S_WIDTH, S_HEIGHT, moons, filename)
+
+    call deplace_les_planetes(moons)
+
+  enddo
+
+end subroutine
+
+!-----------------------------------------------------------------------
+subroutine deplace_les_planetes(moons)
+  type(massbody), intent(inout)    :: moons(:)
+
+  integer                 :: foo
+  real                    :: depx, depy
+
+  do foo=1, ubound(moons, 1)
+
+    ! print *, "----- deplace ",foo, "serial ", moons(foo)%serial
+    depx = moons(foo)%speed * sin(moons(foo)%heading)
+    depy = moons(foo)%speed * cos(moons(foo)%heading)
+    moons(foo)%posx = moons(foo)%posx + depx
+    moons(foo)%posy = moons(foo)%posy + depy
+
+    !-
+    !   ici se pose une question pertinente sur la gestion des
+    !   bords du chanmp. Cclippin or Boucing ?
+    !-
+    if (moons(foo)%posx .GT. S_WIDTH)   moons(foo)%posx = 0.0
+    if (moons(foo)%posy .GT. S_HEIGHT)  moons(foo)%posy = 0.0
+    if (moons(foo)%posx .LT. 0)         moons(foo)%posx = S_WIDTH
+    if (moons(foo)%posy .LT. 0)         moons(foo)%posy = S_HEIGHT
+
+    moons(foo)%heading = moons(foo)%heading + (0.08*rand())
+    if (moons(foo)%heading .GT. 6.2831853) moons(foo)%heading = 0.0
+
+  enddo
+
+end subroutine
+!-----------------------------------------------------------------------
+!-----------------------------------------------------------------------
 
 end program
+
+
+
diff --git a/GravityField/encode.sh b/GravityField/encode.sh
index d2d5ad2..2fa923b 100755
--- a/GravityField/encode.sh
+++ b/GravityField/encode.sh
@@ -12,14 +12,31 @@ SDIR="$1"
 FNAME="$2"
 echo "Encoding from " $SDIR " to " $FNAME
 
+#
+#  trying to guess the format of inoput files
+#
+firstfile=$(ls -1 $SDIR/* | head -1)
+echo "first file :" $firstfile
+filetype=$(file $firstfile | awk '{ print $2 }')
+echo "file type  :" $filetype
+
+case  $filetype in
+	PNG)		extension=".png"		;;
+	Netpbm)		extension=".pgm"		;;
+	*)		extension=".binary"		;;
+esac
+echo "extension  :" $extension
+
 TITLE='---{ experimental gravity field }---'
 
 ffmpeg  -nostdin					\
 	-loglevel warning				\
-	-y -r 30 -f image2 -i $SDIR/%05d.pgm 		\
+	-y -r 30 -f image2 -i ${SDIR}/%05d${extension}	\
 	-metadata artist='---{ tTh }---'		\
 	-metadata title="${TITLE}"			\
 	-c:v libx264 -pix_fmt yuv420p			\
 	$FNAME
 
+echo
+
 
diff --git a/GravityField/essai.f90 b/GravityField/essai.f90
index 58c073b..5b55988 100644
--- a/GravityField/essai.f90
+++ b/GravityField/essai.f90
@@ -22,7 +22,7 @@ program essai
   call create_some_planets(planets, 45e5, S_WIDTH, S_HEIGHT)
 
   do foo=0, 1999
-    write (filename, "(a, i5.5, a)") 'WS/', foo, '.pgm'
+    write (filename, "(a, i5.5, a)") 'WS/field/', foo, '.pgm'
     call build_and_write_a_field(S_WIDTH, S_HEIGHT, planets, filename)
     ! print *, trim(filename)
     ! OMG! two magic numbers, wtf?
diff --git a/GravityField/raytrace.sh b/GravityField/raytrace.sh
index 88bfb92..c570df4 100755
--- a/GravityField/raytrace.sh
+++ b/GravityField/raytrace.sh
@@ -2,7 +2,7 @@
 
 set -e
 
-POVOPT=" -q9 +a -W800 -H600 +WT2 -d -v "
+POVOPT=" -q9 +a -W1280 -H1024 +WT2 -d -v "
 SOURCE="vision.pov"
 TMPF="/dev/shm/gravfield.png"
 
@@ -14,14 +14,20 @@ clock=$1
 
 povray -i${SOURCE} -K${clock} $POVOPT -O${TMPF} 2> pov.stderr
 
-timestamp=$(date | tr '01' 'Ol')
-outfile=$(printf "WS/%05d.png" $clock)
+timestamp=$(date -u +'%F %H:%M' | tr '01' 'Ol')
+texte=$(printf "pass %04d" $clock | tr '01' 'Ol')
+outfile=$(printf "WS/troid/%05d.png" $clock)
+echo  $timestamp $texte $outfile
 
 convert	${TMPF}				\
-	-pointsize 14			\
+	-pointsize 16			\
 	-font Courier-Bold		\
 	-fill Orange			\
 	-annotate +10+16  "$timestamp"	\
+	-annotate +10+34  "$texte"	\
+	-pointsize 8			\
+	-gravity south-west		\
+	-annotate +10+6 "tTh & Konrad"	\
 	${outfile}
 }
 
@@ -31,12 +37,13 @@ for foo in $(seq 0 1999)
 do
 	echo '............' $foo
 	une_passe $foo
+	exit
 done
 
 ffmpeg  -nostdin					\
 	-loglevel warning				\
-	-y -r 30 -f image2 -i WS/%05d.png 		\
-	-metadata artist='---{ tTh }---'		\
+	-y -r 30 -f image2 -i WS/trid/%05d.png 		\
+	-metadata artist='---{ tTh and Konrad }---'	\
 	-metadata title="Experiment on Gravity Field"	\
 	-c:v libx264 -pix_fmt yuv420p			\
 	bar.mp4
diff --git a/GravityField/realfield.f90 b/GravityField/realfield.f90
index ab62aac..bf73f49 100644
--- a/GravityField/realfield.f90
+++ b/GravityField/realfield.f90
@@ -13,8 +13,8 @@ module realfield
 !-
 type massbody
   real                  :: posx, posy
-  real                  :: heading       = 33.21
-  real                  :: speed         = 1.007
+  real                  :: heading       = 0.21
+  real                  :: speed         = 1.017
   real                  :: mass          = 1.0
   integer               :: serial        = 666
 end type
@@ -39,7 +39,7 @@ subroutine barycentre_bodies(astres)
   enddo
   cx = cx / real(ubound(astres, 1))
   cy = cy / real(ubound(astres, 1))
-  print *, cx, cy
+  print *, 'barycentre:', cx, cy
 
 end subroutine
 !-----------------------------------------------------------------------
@@ -57,16 +57,21 @@ subroutine create_some_planets(planets, coef, sx, sy)
   fmt = "(I4, '  | ', 2(F10.2, '  '), ' | ', 2F9.3, '  ', e12.3, I7)"
 
   do foo=1, ubound(planets, 1)
+    !-
+    !   the first planet is the home of Johnny Root
+    !-
     if (foo .EQ. 1) then
-      planets(1)%posx   = 10
-      planets(1)%posy   = 10
-      planets(1)%mass   = 7e8
+      planets(1)%posx   = sx / 2
+      planets(1)%posy   = sy / 2
+      planets(1)%mass   = 37e8
       planets(1)%serial = 1337
     else
       planets(foo)%posx     = rand() * real(sx-1)
       planets(foo)%posy     = rand() * real(sy-1)
       planets(foo)%mass     = 7e6 + coef*foo
-      planets(foo)%serial   = foo
+      planets(foo)%heading  = 3.14159 * rand()
+      if (rand() .LT. 0.01) planets(foo)%speed = 2.718
+      planets(foo)%serial   = foo*2 + 120
     endif
     write (*, fmt) foo, planets(foo)
   enddo
diff --git a/GravityField/runme.sh b/GravityField/runme.sh
index d20b182..7d4ccf0 100755
--- a/GravityField/runme.sh
+++ b/GravityField/runme.sh
@@ -6,5 +6,5 @@ make essai
 
 time ./essai | tee essai.log
 
-./encode.sh WS/ foo.mp4
+./encode.sh WS/field/ foo.mp4
 
diff --git a/GravityField/vision.pov b/GravityField/vision.pov
index 8f12092..7737c29 100644
--- a/GravityField/vision.pov
+++ b/GravityField/vision.pov
@@ -11,16 +11,15 @@ global_settings {
 		max_trace_level 6
 		}
 
-
 #include  "colors.inc"
 
+#declare NormClock = clock / 2000.01;
+
 // ----------------------------------------------------------------------
 
-#declare HFDIR  = "WS/";
+#declare HFDIR  = "WS/nanim/";
 #declare HFCK   = mod(clock, 2000);
-
 #declare HFNAME = concat(HFDIR, str(HFCK , -5, 0), ".pgm");
-
 #debug concat("- - - - - - - ", HFNAME, "\n")
 
 #declare GravityField = object
@@ -32,25 +31,27 @@ height_field {
 	}
 texture {
 	pigment { color Gray80 }
-	finish { phong 2.0 }
+	finish { phong 0.50 }
 	}
 }
 
-object { GravityField scale <4, 1, 4> }
+object { GravityField scale <4, 0.70, 4> }
 
 // ----------------------------------------------------------------------
 
+cylinder { <0, -0.5, 0>, <0, 1, 0>, 0.0175 pigment { color Red } }
+
 light_source { < -2, 9.3, -7>	color Gray90			}
-light_source { < -5, 9.3, -7>	color Orange*0.75		}
-light_source { < -15, 2.3, 17>	color Blue*0.50			}
+light_source { < -6, 9.3, -8>	color Orange*0.75		}
+light_source { < -15, 2.3, 17>	color Green*0.25			}
 
 // ----------------------------------------------------------------------
 
 camera	{
-	location	<-8, 4, 3>
+	location	<-8, 4-NormClock, 1 + 3*NormClock>
 	look_at		<0, 0, 0>
 	right		x*image_width/image_height
-	angle		35
+	angle		34
 	}
 
 // ----------------------------------------------------------------------