diff --git a/src/_impl/_in_shape_impl.scad b/src/_impl/_in_shape_impl.scad
new file mode 100644
index 00000000..7805da94
--- /dev/null
+++ b/src/_impl/_in_shape_impl.scad
@@ -0,0 +1,37 @@
+use <__comm__/__in_line.scad>;
+
+function _in_shape_in_line_equation(edge, pt) = 
+    let(
+        x1 = edge[0][0],
+        y1 = edge[0][1],
+        x2 = edge[1][0],
+        y2 = edge[1][1],
+        a = (y2 - y1) / (x2 - x1),
+        b = y1 - a * x1
+    )
+    (pt[1] == a * pt[0] + b);
+
+function _in_shape_in_any_edges(edges, pt, epsilon) = 
+    let(
+        leng = len(edges),
+        maybe_last = [for(i = 0; i < leng && !__in_line(edges[i], pt, epsilon); i = i + 1) i][leng - 1] 
+    )
+    is_undef(maybe_last);
+
+function _in_shape_interpolate_x(y, p1, p2) = 
+    p1[1] == p2[1] ? p1[0] : (
+        p1[0] + (p2[0] - p1[0]) * (y - p1[1]) / (p2[1] - p1[1])
+    );
+    
+function _in_shape_does_pt_cross(pts, i, j, pt) = 
+    ((pts[i][1] > pt[1]) != (pts[j][1] > pt[1])) &&
+    (pt[0] < _in_shape_interpolate_x(pt[1], pts[i], pts[j]));
+    
+
+function _in_shape_sub(shapt_pts, leng, pt, cond, i, j) =
+    j == leng ? cond : (
+        _in_shape_does_pt_cross(shapt_pts, i, j, pt) ? 
+            _in_shape_sub(shapt_pts, leng, pt, !cond, j, j + 1) :
+            _in_shape_sub(shapt_pts, leng, pt, cond, j, j + 1)
+    );
+ 
\ No newline at end of file
diff --git a/src/in_shape.scad b/src/in_shape.scad
index a1afa0a3..7062ef6e 100644
--- a/src/in_shape.scad
+++ b/src/in_shape.scad
@@ -8,45 +8,9 @@
 *
 **/
 
-include <__comm__/__to3d.scad>;
-include <__comm__/__lines_from.scad>;
-include <__comm__/__in_line.scad>;
+use <__comm__/__lines_from.scad>;
+use <_impl/_in_shape_impl.scad>;
 
-function _in_shape_in_line_equation(edge, pt) = 
-    let(
-        x1 = edge[0][0],
-        y1 = edge[0][1],
-        x2 = edge[1][0],
-        y2 = edge[1][1],
-        a = (y2 - y1) / (x2 - x1),
-        b = y1 - a * x1
-    )
-    (pt[1] == a * pt[0] + b);
-
-function _in_shape_in_any_edges(edges, pt, epsilon) = 
-    let(
-        leng = len(edges),
-        maybe_last = [for(i = 0; i < leng && !__in_line(edges[i], pt, epsilon); i = i + 1) i][leng - 1] 
-    )
-    is_undef(maybe_last);
-
-function _in_shape_interpolate_x(y, p1, p2) = 
-    p1[1] == p2[1] ? p1[0] : (
-        p1[0] + (p2[0] - p1[0]) * (y - p1[1]) / (p2[1] - p1[1])
-    );
-    
-function _in_shape_does_pt_cross(pts, i, j, pt) = 
-    ((pts[i][1] > pt[1]) != (pts[j][1] > pt[1])) &&
-    (pt[0] < _in_shape_interpolate_x(pt[1], pts[i], pts[j]));
-    
-
-function _in_shape_sub(shapt_pts, leng, pt, cond, i, j) =
-    j == leng ? cond : (
-        _in_shape_does_pt_cross(shapt_pts, i, j, pt) ? 
-            _in_shape_sub(shapt_pts, leng, pt, !cond, j, j + 1) :
-            _in_shape_sub(shapt_pts, leng, pt, cond, j, j + 1)
-    );
- 
 function in_shape(shapt_pts, pt, include_edge = false, epsilon = 0.0001) = 
     let(
         leng = len(shapt_pts),