diff --git a/src/arc.scad b/src/arc.scad
index 371c2926..0e7cae55 100644
--- a/src/arc.scad
+++ b/src/arc.scad
@@ -1,7 +1,7 @@
 /**
 * arc.scad
 *
-* Create an arc. You can pass a 2 element vector to define the central angle. 
+* Creates an arc. You can pass a 2 element vector to define the central angle. 
 * Its $fa, $fs and $fn parameters are consistent with the circle module.
 * It depends on the circular_sector module so you have to include circular_sector.scad.
 * 
diff --git a/src/archimedean_spiral.scad b/src/archimedean_spiral.scad
index 57237209..e8397dd7 100644
--- a/src/archimedean_spiral.scad
+++ b/src/archimedean_spiral.scad
@@ -1,12 +1,12 @@
 /**
 * archimedean_spiral.scad
 *
-*  Get all points and angles on the path of an archimedean_spiral. The distance between two  points is almost constant. 
+*  Gets all points and angles on the path of an archimedean_spiral. The distance between two  points is almost constant. 
 * 
 *  It returns a vector of [[x, y], angle]. 
 *
-*  In polar coordinates (r, £c) Archimedean spiral can be described by the equation r = b£c where
-*  £c is measured in radians. For being consistent with OpenSCAD, the function here use degrees.
+*  In polar coordinates (r, �c) Archimedean spiral can be described by the equation r = b�c where
+*  �c is measured in radians. For being consistent with OpenSCAD, the function here use degrees.
 *
 *  An init_angle less than 180 degrees is not recommended because the function uses an approximate 
 *  approach. If you really want an init_angle less than 180 degrees, a larger arm_distance 
@@ -39,8 +39,8 @@ function _find_radians(b, point_distance, radians, n, count = 1) =
     );
 
 /* 
-    In polar coordinates (r, £c) Archimedean spiral can be described by the equation r = b£c where
-    £c is measured in radians. For being consistent with OpenSCAD, the function here use degrees.
+    In polar coordinates (r, �c) Archimedean spiral can be described by the equation r = b�c where
+    �c is measured in radians. For being consistent with OpenSCAD, the function here use degrees.
     An init_angle angle less than 180 degrees is not recommended because the function uses an 
     approximate approach. If you really want an angle less than 180 degrees, a larger arm_distance 
     is required. To avoid a small error value at the calculated distance between two points, you 
diff --git a/src/bend.scad b/src/bend.scad
index 7215d112..cd2f551a 100644
--- a/src/bend.scad
+++ b/src/bend.scad
@@ -1,7 +1,7 @@
 /**
 * bend.scad
 *
-* Bend a 3D object into an arc shape. 
+* Bends a 3D object into an arc shape. 
 * 
 * @copyright Justin Lin, 2017
 * @license https://opensource.org/licenses/lgpl-3.0.html
diff --git a/src/box_extrude.scad b/src/box_extrude.scad
index 29b619d7..72ae0ece 100644
--- a/src/box_extrude.scad
+++ b/src/box_extrude.scad
@@ -1,7 +1,7 @@
 /**
 * box_extrude.scad
 *
-* Create a box (container) from a 2D object.
+* Creates a box (container) from a 2D object.
 * 
 * @copyright Justin Lin, 2017
 * @license https://opensource.org/licenses/lgpl-3.0.html
diff --git a/src/circular_sector.scad b/src/circular_sector.scad
index 52ce36cd..ab92c0c0 100644
--- a/src/circular_sector.scad
+++ b/src/circular_sector.scad
@@ -1,7 +1,7 @@
 /**
 * circular_sector.scad
 *
-* Create a circular sector. You can pass a 2 element vector to define the central angle. Its $fa, $fs and $fn parameters are consistent with the circle module.
+* Creates a circular sector. You can pass a 2 element vector to define the central angle. Its $fa, $fs and $fn parameters are consistent with the circle module.
 * 
 * @copyright Justin Lin, 2017
 * @license https://opensource.org/licenses/lgpl-3.0.html
diff --git a/src/helix.scad b/src/helix.scad
index 395904dd..3f7b02c1 100644
--- a/src/helix.scad
+++ b/src/helix.scad
@@ -1,7 +1,7 @@
 /**
 * helix.scad
 *
-* Get all points on the path of a spiral around a cylinder. 
+* Gets all points on the path of a spiral around a cylinder. 
 * Its $fa, $fs and $fn parameters are consistent with the cylinder module.
 * It depends on the circle_path module so you have to include circle_path.scad.
 * 
diff --git a/src/hollow_out.scad b/src/hollow_out.scad
index 23f6cb55..fa6814eb 100644
--- a/src/hollow_out.scad
+++ b/src/hollow_out.scad
@@ -1,7 +1,7 @@
 /**
 * hollow_out.scad
 *
-* Hollow out a 2D object. 
+* Hollows out a 2D object. 
 * 
 * @copyright Justin Lin, 2017
 * @license https://opensource.org/licenses/lgpl-3.0.html