diff --git a/Fonderie/sfx.c b/Fonderie/sfx.c
index 0a8abfe5..4d29b6cb 100644
--- a/Fonderie/sfx.c
+++ b/Fonderie/sfx.c
@@ -127,6 +127,9 @@ static int pixel_trinitron(FloatImg *pimg, int pos[4], float *fvals)
 int		x, y, pline, off;
 int		ym;
 
+// fprintf(stderr, ">>> %s ( %p  %d,%d,%d,%d )\n", __func__, pimg,
+//			pos[0], pos[1], pos[2], pos[3]);
+
 fimg_clear_rectangle(pimg, pos);
 
 ym = pos[1]+pos[3]-1;
@@ -137,6 +140,7 @@ for (y=pos[1]; y<ym; y++) {
 	pline = y*pimg->width;
 	for (x=0; x<5; x++) {
 		off = pline + (x+pos[0]);
+
 		/* wtf i'm doing here ? */
 		if ( (pos[1]==y) || (ym-1==y) ) {
 			pimg->R[off]    = fvals[0] * FDIM;
@@ -179,21 +183,22 @@ fprintf(stderr, ">>> %s ( %p %d )\n", __func__, pimg, notused);
  *   And this mistake is all around the code /o\
  *
  */
-#define STP  8			/* stepd for x & y axex */
+#define STP  15			/* stepd for x & y axex */
 coo[2] = coo[3] = STP;
 
-for (y=0; y < pimg->height; y+=STP) {
+for (y=0; y < pimg->height-STP; y+=STP) {
 	coo[1] = y;
-	for (x=0; x < pimg->width; x+=STP) {
+	for (x=0; x < pimg->width-STP; x+=STP) {
 		coo[0] = x;
 		foo = stat_zone(pimg, coo, vals);
 		if (foo)	abort();
-		/* next step : plot the datas */
-		// XXX fprintf(stderr, "%s    %6d    %6d\n", __func__, x, y);
 		pixel_trinitron(pimg, coo, vals);
 		}
 	}
 #undef STP
+
+// fprintf(stderr, "   end trinitron\n");		// XXX
+
 return 0;
 }
 /* -------------------------------------------------------------- */