diff --git a/pr/posbi/GNUmakefile b/pr/posbi/GNUmakefile
new file mode 100644
index 0000000..99229cb
--- /dev/null
+++ b/pr/posbi/GNUmakefile
@@ -0,0 +1,24 @@
+# what's where?
+include GNUmakevars
+
+
+all: \
+	test-mesh.png \
+	test-posbi.png \
+
+
+%.ppm: %.pov
+	$(POVRAY) +W$(WIDTH) +H$(HEIGHT) +V -I$< +L$(POVINC) +D +FP
+
+%.png: %.pov
+	$(POVRAY) +V -I$< +L$(POVINC) +D +FN
+
+%.pov: make%
+	$< > $@
+
+test-posbi.png: test-posbi.pov \
+    posbi.pov 
+	$(POVRAY) +W800 +H600 +V -I$< +L$(POVINC) +D +FN
+
+%.gif: %.ppm
+	ppmquant 256 $< | ppmtogif > $@
diff --git a/pr/posbi/posbi.pov b/pr/posbi/posbi.pov
new file mode 100644
index 0000000..8fb5293
--- /dev/null
+++ b/pr/posbi/posbi.pov
@@ -0,0 +1,63 @@
+#local RND1 = seed(1);
+#local R1 = 1000;
+#local R2 = 0;
+
+#local C = array[2][2][2] {
+    {
+	{
+	    <-R1 + R2 * (rand(RND1)*2-1), -R1 + R2 * (rand(RND1)*2-1), -R1 + R2 * (rand(RND1)*2-1)>,
+	    <-R1 + R2 * (rand(RND1)*2-1), -R1 + R2 * (rand(RND1)*2-1), +R1 + R2 * (rand(RND1)*2-1)>,
+	},
+	{
+	    <-R1 + R2 * (rand(RND1)*2-1), +R1 + R2 * (rand(RND1)*2-1), -R1 + R2 * (rand(RND1)*2-1)>,
+	    <-R1 + R2 * (rand(RND1)*2-1), +R1 + R2 * (rand(RND1)*2-1), +R1 + R2 * (rand(RND1)*2-1)>,
+	},
+    }
+    {
+	{
+	    <+R1 + R2 * (rand(RND1)*2-1), -R1 + R2 * (rand(RND1)*2-1), -R1 + R2 * (rand(RND1)*2-1)>,
+	    <+R1 + R2 * (rand(RND1)*2-1), -R1 + R2 * (rand(RND1)*2-1), +R1 + R2 * (rand(RND1)*2-1)>,
+	},
+	{
+	    <+R1 + R2 * (rand(RND1)*2-1), +R1 + R2 * (rand(RND1)*2-1), -R1 + R2 * (rand(RND1)*2-1)>,
+	    <+R1 + R2 * (rand(RND1)*2-1), +R1 + R2 * (rand(RND1)*2-1), +R1 + R2 * (rand(RND1)*2-1)>,
+	},
+    }
+};
+
+#declare posbi = mesh2 {
+    vertex_vectors {
+	14,
+	C[0][0][0],
+	C[0][0][1],
+	C[0][1][0],
+	C[0][1][1],
+	C[1][0][0],
+	C[1][0][1],
+	C[1][1][0],
+	C[1][1][1],
+	(C[0][0][0] + C[0][0][1] + C[0][1][0] + C[0][1][1])/4,
+	(C[1][0][0] + C[1][0][1] + C[1][1][0] + C[1][1][1])/4,
+	(C[0][0][0] + C[0][0][1] + C[1][0][0] + C[1][0][1])/4,
+	(C[0][1][0] + C[0][1][1] + C[1][1][0] + C[1][1][1])/4,
+	(C[0][0][0] + C[0][1][0] + C[1][0][0] + C[1][1][0])/4,
+	(C[0][0][1] + C[0][1][1] + C[1][0][1] + C[1][1][1])/4,
+    }
+    texture_list {
+	4
+	texture { pigment { color rgb <0.5, 0.5, 0.5> } }
+	texture { pigment { color rgb <0.9, 0.5, 0.5> } }
+	texture { pigment { color rgb <0.5, 0.9, 0.5> } }
+	texture { pigment { color rgb <0.5, 0.5, 0.9> } }
+    }
+    face_indices {
+	24
+	<0, 1, 8>, 0,	<1, 2, 8>, 1,	<2, 3, 8>, 2,	<3, 0, 8>, 3,
+	<4, 5, 9>, 0,	<5, 6, 9>, 1,	<6, 7, 9>, 2,	<7, 4, 9>, 3,
+	<0, 1, 10>, 0	<1, 4, 10>, 1,	<4, 5, 10>, 2,	<5, 0, 10>, 3,
+	<2, 3, 11>, 0	<3, 6, 11>, 1,	<6, 7, 11>, 2,	<7, 2, 11>, 3,
+	<0, 2, 12>, 0	<2, 4, 12>, 1,	<4, 6, 12>, 2,	<6, 0, 12>, 3,
+	<1, 3, 13>, 0	<3, 5, 13>, 1,	<5, 7, 13>, 2,	<7, 1, 13>, 3,
+    }
+
+}
diff --git a/pr/posbi/povray.ini b/pr/posbi/povray.ini
new file mode 100644
index 0000000..49be253
--- /dev/null
+++ b/pr/posbi/povray.ini
@@ -0,0 +1,6 @@
++MB5
++QR
++A
++HTN
++fp +w640 +h480 +d1 
+display_gamma = 2.2
diff --git a/pr/posbi/test-mesh.pov b/pr/posbi/test-mesh.pov
new file mode 100644
index 0000000..3ca6517
--- /dev/null
+++ b/pr/posbi/test-mesh.pov
@@ -0,0 +1,46 @@
+global_settings {
+        assumed_gamma 1.0
+        ambient_light rgb<0.5, 0.5, 0.5>
+}
+background { color rgb<0.2, 0.4, 0.8>  }
+light_source {
+    <20000, 20000, 20000>
+    color 1
+}
+
+#local CP = <+2, +0, +5>;
+light_source {
+    CP
+    color 0.5
+}
+camera {
+        location CP
+        look_at <-0, 0, -0>
+}
+
+
+mesh2 {
+    vertex_vectors {
+	5,
+	<-1, -1, 0>,
+	<-1, +1, 0>,
+	<+1, -1, 0>,
+	<+1, +1, 0>,
+	< 0,  0, 0>,
+    }
+    texture_list {
+	4
+	texture { pigment { color rgb <0.5, 0.5, 0.5> } }
+	texture { pigment { color rgb <0.9, 0.5, 0.5> } }
+	texture { pigment { color rgb <0.5, 0.9, 0.5> } }
+	texture { pigment { color rgb <0.5, 0.5, 0.9> } }
+    }
+    face_indices {
+	4
+	<0, 1, 4>, 0, 0, 0,
+	<1, 2, 4>, 1, 1, 1,
+	<2, 3, 4>, 2, 2, 2,
+	<3, 0, 4>, 3, 3, 3,
+    }
+}
+
diff --git a/pr/posbi/test-posbi.pov b/pr/posbi/test-posbi.pov
new file mode 100644
index 0000000..14f4379
--- /dev/null
+++ b/pr/posbi/test-posbi.pov
@@ -0,0 +1,80 @@
+#include "colors.inc"
+#include "shapes.inc"
+#include "textures.inc"
+#include "metals.inc"
+#include "stones.inc"
+
+#declare SCHNITT_1 = 1;	// Quadrant -/*/-
+
+global_settings {
+        assumed_gamma 1.0
+        ambient_light rgb<0.5, 0.5, 0.5>
+}
+background { color rgb<0.2, 0.4, 0.8>  }
+light_source {
+    <-20000, 20000, -20000>
+    color White
+}
+
+#local CP = <+5000, +2500, -1000>;
+light_source {
+    CP
+    color White*0.5
+}
+//camera {
+//	location CP
+//	look_at <-0, -0, -0>
+//	orthographic
+//	up <0, 4000, 0>
+//	right <8000, 0, 0>
+//}
+camera {
+        location CP
+        look_at <-0, 900, -0>
+}
+
+#include "posbi.pov"
+
+    object {
+	posbi
+    }
+
+#declare gatter =
+    union {
+	#local I = -50;
+	#while (I <= 50) 
+	    #switch (mod(I, 10) )
+	    #case (0)
+		#local Color = color <0, 1, 0>;
+		#local R = 0.2;
+		#break;
+	    #case (5)
+	    #case (-5)
+		#local Color = color <1, 0, 0>;
+		#local R = 0.15;
+		#break;
+	    #else 
+		#local Color = color <0, 0, 1>;
+		#local R = 0.1;
+	    #end
+		    
+	    cylinder {
+		<I, -50, 0>, <I, +50, 0> R
+		texture {pigment { color Color } }
+	    }
+	    cylinder {
+		<-50, I, 0>, <+50, I, 0> R
+		texture {pigment { color Color } }
+	    }
+	    #local I = I + 1;
+	#end
+
+    }
+
+object {
+    gatter 
+    rotate <90, 0, 0>
+    scale 100
+}
+
+