diff --git a/src/experimental/_impl/_convex_center_p_impl.scad b/src/experimental/_impl/_convex_center_p_impl.scad
new file mode 100644
index 00000000..0bd9d2ab
--- /dev/null
+++ b/src/experimental/_impl/_convex_center_p_impl.scad
@@ -0,0 +1,2 @@
+function _sum(lt, leng, i = 0) =
+    i == leng ? [0, 0] : lt[i] + _sum(lt, leng, i + 1);