diff --git a/src/experimental/ptf_c2sphere.scad b/src/experimental/ptf_c2sphere.scad
new file mode 100644
index 00000000..ab687f71
--- /dev/null
+++ b/src/experimental/ptf_c2sphere.scad
@@ -0,0 +1,29 @@
+use <ptf/ptf_rotate.scad>;
+
+function ptf_c2sphere(point, radius) = 
+    let(
+	    za = atan2(point[1], point[0]),
+		ya = 90 * norm(point) / radius
+	)
+	ptf_rotate([radius * sin(ya), 0, radius * cos(ya)], za);
+
+/*
+use <experimental/tile_penrose3.scad>;
+use <experimental/ptf_c2sphere.scad>;
+
+r_circle = 19;
+points = [
+    for(r = [1:r_circle]) 
+	    for(a = [0:30:330])
+            [r * cos(a), r * sin(a)]		
+];
+
+radius = 10;
+for(p = points) {
+    #translate(p)
+	    sphere(1);
+		
+    translate(ptf_c2sphere(p, radius))
+	    sphere(1);
+}
+*/
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