diff --git a/experiment/Makefile b/experiment/Makefile
index 68b0e82..bcaa853 100644
--- a/experiment/Makefile
+++ b/experiment/Makefile
@@ -2,7 +2,7 @@
 #  experiments
 
 
-COPT = -Wall -fpic -g -DDEBUG_LEVEL=0 -lm
+COPT = -Wall -fpic -g -DDEBUG_LEVEL=1 -lm
 DEPS = ../floatimg.h  ../libfloatimg.a Makefile
 LIBS = -ltiff -lpnglite -lcfitsio
 
diff --git a/experiment/assemblage.c b/experiment/assemblage.c
index 6cca803..d6ac38d 100644
--- a/experiment/assemblage.c
+++ b/experiment/assemblage.c
@@ -12,6 +12,12 @@
 int		verbosity;
 
 /* ---------------------------------------------- ~~~~~~~~~~~~~~~~ */
+/*
+ *	le prototype de base avec trop peu de parametres, mais
+ *	c'est assez dur de formaliser la structure des informations
+ *	a transmettre de fonction en fonction, et commant on peut
+ *	integrer cette mecanique dans singlepass.c ?!#@
+ */
 int premier_essai(int largeur, int hauteur, char *outname)
 {
 FloatImg	grande, incrust;
@@ -36,12 +42,15 @@ if (foo) {
 	return -1;
 	}
 
-foo = incrustator_0(&incrust, &grande, 333, 333, 0);
+#define FLAGS   0
+foo = incrustator_0(&incrust, &grande, 111, 111, FLAGS);
+#undef FLAGS
 if (foo) {
-	fprintf(stderr, "%s: Kkrkr %d sur incrustator_0\n", __func__, foo);
+	fprintf(stderr, "%s: err %d sur incrustator_0\n", __func__, foo);
 	return -1;
 	}
 
+
 foo =  fimg_export_picture(&grande, outname, 0);
 if (foo) {
 	fprintf(stderr, "%s: error %d export '%s'\n", __func__,
diff --git a/experiment/incrustator.c b/experiment/incrustator.c
index eed2e45..096e33c 100644
--- a/experiment/incrustator.c
+++ b/experiment/incrustator.c
@@ -4,6 +4,7 @@
 
 #include  <stdio.h>
 #include  <string.h>
+#include  <stdlib.h>
 
 #include  "../floatimg.h"
 
@@ -11,11 +12,44 @@
 
 extern int 		verbosity;
 
+/* ---------------------------------------------------------------- */
+static int check_boundaries(FloatImg *from, FloatImg *to, FimgArea51 *a51)
+{
+
+#if DEBUG_LEVEL
+fprintf(stderr, ">>> %s ( %p %p %p )\n", __func__, from, to, a51);
+fimg_printdims("from", from);
+fimg_printdims("to  ", to);
+#endif
+
+/* just a small molly-guard */
+if ( (a51->w < 0) || (a51->h < 0) ) {
+	fprintf(stderr, "%s: fubar on %p\n", __func__, a51);
+	abort();		/* FY Bro ! */
+	}
+
+return -1;
+}
+/* ---------------------------------------------------------------- */
+static int move_pixels(FloatImg *from, FloatImg *to,
+				FimgArea51 *a51, int flags)
+{
+
+#if DEBUG_LEVEL
+fprintf(stderr, ">>> %s ( %p %p %p 0x%04x )\n", __func__,
+				from, to, a51, flags);
+#endif
+
+return -1;
+}
 /* ---------------------------------------------------------------- */
 int incrustator_0(FloatImg *psrc, FloatImg *pdst,
 				int xpos, int ypos, int flags)
 {
-int	y, srcpos, dstpos, szl;
+int		y, srcpos, dstpos, szl;
+int		foo;
+
+FimgArea51	area;
 
 #if DEBUG_LEVEL
 fprintf(stderr, ">>> %s ( %p %p %d %d 0x%04X\n", __func__, psrc, pdst,
@@ -28,6 +62,10 @@ if (verbosity > 1) {
 	}
 
 /* check boudaries */
+area.x = xpos;		area.y = ypos;
+area.w = psrc->width;	area.h = psrc->height;
+foo = check_boundaries(psrc, pdst, &area);
+
 if (	(xpos < 0)  || (xpos > pdst->width  - psrc->width)  ||
 	(ypos < 0)  || (ypos > pdst->height - psrc->height) ) {
 	fprintf(stderr, "%s: boudary error\n", __func__);
diff --git a/experiment/incrustator.h b/experiment/incrustator.h
index 9cd2b88..1e75cd6 100644
--- a/experiment/incrustator.h
+++ b/experiment/incrustator.h
@@ -2,6 +2,11 @@
  *		incrustator experimental
  */
 
+typedef struct	{
+	int		w, h;
+	int		x, y;
+	unsigned long	magic;
+		} FimgArea51;
 
 int incrustator_0(FloatImg *psrc, FloatImg *pdst,
 				int xpos, int ypos, int flags);
diff --git a/experiment/plasma314.c b/experiment/plasma314.c
deleted file mode 100644
index 83f9df3..0000000
--- a/experiment/plasma314.c
+++ /dev/null
@@ -1,6 +0,0 @@
-/*
- *		PLASMA !!!
- */
-
-#include  <stdio.h>
-