diff --git a/geometry.scad b/geometry.scad
index b145c6f..c8bb2a3 100644
--- a/geometry.scad
+++ b/geometry.scad
@@ -959,7 +959,7 @@ function plane_from_polygon(poly, fast=false, eps=EPSILON) =
 //   plane_normal(plane);
 // Description:
 //   Returns the unit length normal vector for the given plane.
-// Argument:
+// Arguments:
 //   plane = The `[A,B,C,D]` plane definition where `Ax+By+Cz=D` is the formula of the plane.
 function plane_normal(plane) =
     assert( _valid_plane(plane), "Invalid input plane." )
@@ -973,7 +973,7 @@ function plane_normal(plane) =
 //   Returns coeficient D of the normalized plane equation `Ax+By+Cz=D`, or the scalar offset of the plane from the origin.
 //   This value may be negative.
 //   The absolute value of this coefficient is the distance of the plane from the origin.
-// Argument:
+// Arguments:
 //   plane = The `[A,B,C,D]` plane definition where `Ax+By+Cz=D` is the formula of the plane.
 function plane_offset(plane) =
     assert( _valid_plane(plane), "Invalid input plane." )
@@ -1046,7 +1046,7 @@ function projection_on_plane(plane, points) =
 //   pt = plane_point_nearest_origin(plane);
 // Description:
 //   Returns the point on the plane that is closest to the origin.
-// Argument:
+// Arguments:
 //   plane = The `[A,B,C,D]` plane definition where `Ax+By+Cz=D` is the formula of the plane.
 function plane_point_nearest_origin(plane) =
     let( plane = normalize_plane(plane) )
@@ -1072,6 +1072,7 @@ function distance_from_plane(plane, point) =
     let( plane = normalize_plane(plane) )
     point3d(plane)* point - plane[3];
 
+
 // Returns [POINT, U] if line intersects plane at one point.
 // Returns [LINE, undef] if the line is on the plane.
 // Returns undef if line is parallel to, but not on the given plane.
@@ -1594,7 +1595,6 @@ function circle_circle_tangents(c1,r1,c2,r2,d1,d2) =
     ];
 
 
-
 // Function: circle_line_intersection()
 // Usage:
 //   isect = circle_line_intersection(c,r,line,<bounded>,<eps>);
@@ -1627,7 +1627,6 @@ function circle_line_intersection(c,r,line,d,bounded=false,eps=EPSILON) =
              let( offset = sqrt(r*r-d*d),
                   uvec=unit(line[1]-line[0])
              ) [closest-offset*uvec, closest+offset*uvec]
-
   )
   [for(p=isect)
      if ((!bounded[0] || (p-line[0])*(line[1]-line[0])>=0)
@@ -1635,7 +1634,6 @@ function circle_line_intersection(c,r,line,d,bounded=false,eps=EPSILON) =
 
 
 
-
 // Section: Pointlists
 
 
@@ -1913,24 +1911,23 @@ function align_polygon(reference, poly, angles, cp) =
 function centroid(poly, eps=EPSILON) =
     assert( is_path(poly,dim=[2,3]), "The input must be a 2D or 3D polygon." )
     assert( is_finite(eps) && (eps>=0), "The tolerance should be a non-negative value." )
-    let(
-        n = len(poly[0])==2 ? 1 :
-            let( 
-                plane = plane_from_points(poly, fast=true) )
-            assert( !is_undef(plane), "The polygon must be planar." )
-            plane_normal(plane),
-        v0 = poly[0] ,
-        val = sum([for(i=[1:len(poly)-2])
-                        let(
-                           v1 = poly[i],
-                           v2 = poly[i+1],
-                           area = cross(v2-v0,v1-v0)*n
-                           )
-                        [ area, (v0+v1+v2)*area ]
-                    ] )
-          )
-      assert(!approx(val[0],0, eps), "The polygon is self-intersecting or its points are collinear.")
-      val[1]/val[0]/3;
+    let( 
+        n = len(poly[0])==2 ? 1 : 
+            let( plane = plane_from_points(poly, fast=true) ) 
+            assert( !is_undef(plane), "The polygon must be planar." ) 
+            plane_normal(plane), 
+        v0 = poly[0] , 
+        val = sum([for(i=[1:len(poly)-2]) 
+                        let( 
+                           v1 = poly[i], 
+                           v2 = poly[i+1], 
+                           area = cross(v2-v0,v1-v0)*n 
+                           ) 
+                        [ area, (v0+v1+v2)*area ] 
+                    ] ) 
+          ) 
+      assert(!approx(val[0],0, eps), "The polygon is self-intersecting or its points are collinear.") 
+      val[1]/val[0]/3; 
 
 
 
diff --git a/tests/test_geometry.scad b/tests/test_geometry.scad
index 08af88a..f320390 100644
--- a/tests/test_geometry.scad
+++ b/tests/test_geometry.scad
@@ -904,11 +904,11 @@ module test_noncollinear_triple() {
 }
 *test_noncollinear_triple();
 
-
+ 
 module test_centroid() {
     $fn = 24;
     assert_approx(centroid(circle(d=100)), [0,0]);
-    assert_approx(centroid(rect([40,60],rounding=10,anchor=LEFT)), [-20,0]);
+    assert_approx(centroid(rect([40,60],rounding=10,anchor=LEFT)), [-20,0]); 
     assert_approx(centroid(rect([40,60],rounding=10,anchor=FWD)), [0,30]);
     poly = move([1,2.5,3.1],p=rot([12,49,24], p=path3d(circle(10,$fn=33))));
     assert_approx(centroid(poly), [1,2.5,3.1]);