diff --git a/src/experimental/_impl/_convex_hull_impl.scad b/src/experimental/_impl/_convex_hull_impl.scad
index e0a11c6b..5d95d9b0 100644
--- a/src/experimental/_impl/_convex_hull_impl.scad
+++ b/src/experimental/_impl/_convex_hull_impl.scad
@@ -1,7 +1,7 @@
 use <util/slice.scad>;
 
 // oa->ob ct_clk : greater than 0
-function _dir(o, a, b) =
+function _convex_hull_impl_dir(o, a, b) =
     let(
         ox = o[0],
         oy = o[1],
@@ -12,15 +12,15 @@ function _dir(o, a, b) =
     )
     (ax - ox) * (by - oy) - (ay - oy) * (bx - ox);
 
-function _lower_m(chain, p, m) = 
-    (m >= 2 && _dir(chain[m - 2], chain[m - 1], p) <= 0) ? _lower_m(chain, p, m - 1) : m;
+function _convex_hull_convex_hull_lower_m(chain, p, m) = 
+    (m >= 2 && _convex_hull_impl_dir(chain[m - 2], chain[m - 1], p) <= 0) ? _convex_hull_convex_hull_lower_m(chain, p, m - 1) : m;
 
-function lower_chain(points, leng, chain, m, i) =
+function _convex_hull_lower_chain(points, leng, chain, m, i) =
     i == leng ? chain : 
         let(
-            current_m = _lower_m(chain, points[i], m)
+            current_m = _convex_hull_convex_hull_lower_m(chain, points[i], m)
         )
-        lower_chain(
+        _convex_hull_lower_chain(
             points,
             leng,
             concat(slice(chain, 0, current_m), [points[i]]),
@@ -28,16 +28,16 @@ function lower_chain(points, leng, chain, m, i) =
             i + 1
         );
             
-function _upper_m(chain, p, m, t) =
-    (m >= t && _dir(chain[m - 2], chain[m - 1], p) <= 0) ?
-        _upper_m(chain, p, m - 1, t) : m;
+function _convex_hull_upper_m(chain, p, m, t) =
+    (m >= t && _convex_hull_impl_dir(chain[m - 2], chain[m - 1], p) <= 0) ?
+        _convex_hull_upper_m(chain, p, m - 1, t) : m;
         
-function _upper_chain(points, chain, m, t, i) =
+function _convex_hull_upper_chain(points, chain, m, t, i) =
     i < 0 ? chain :
         let(
-            current_m = _upper_m(chain, points[i], m, t)
+            current_m = _convex_hull_upper_m(chain, points[i], m, t)
         )
-        _upper_chain(
+        _convex_hull_upper_chain(
             points,
             concat(slice(chain, 0, current_m), [points[i]]),
             current_m + 1,
diff --git a/src/experimental/convex_hull.scad b/src/experimental/convex_hull.scad
index 4fab8e43..dda0bc55 100644
--- a/src/experimental/convex_hull.scad
+++ b/src/experimental/convex_hull.scad
@@ -5,8 +5,8 @@ function convex_hull(points) =
     let(
         sorted = sort(points, by = "x"),
         leng = len(sorted),
-        lwr_ch = lower_chain(sorted, leng, [], 0, 0),
+        lwr_ch = _convex_hull_lower_chain(sorted, leng, [], 0, 0),
         leng_lwr_ch = len(lwr_ch),
-        chain = _upper_chain(sorted, lwr_ch, leng_lwr_ch, leng_lwr_ch + 1, leng - 2)
+        chain = _convex_hull_upper_chain(sorted, lwr_ch, leng_lwr_ch, leng_lwr_ch + 1, leng - 2)
     )
     [for(i = [0:len(chain) - 2]) chain[i]];
\ No newline at end of file