diff --git a/coords.scad b/coords.scad
index b7bfeaf1..59df5a0a 100644
--- a/coords.scad
+++ b/coords.scad
@@ -29,7 +29,7 @@ function point2d(p, fill=0) = assert(is_list(p)) [for (i=[0:1]) (p[i]==undef)? f
 // Synopsis: Convert a path to 2D. 
 // SynTags: Path
 // Topics: Coordinates, Points, Paths
-// See Also: point2d(), point3d(), path3d()
+// See Also: point2d(), point3d(), path3d(), point4d(), path4d(), hstack()
 // Usage:
 //   pts = path2d(points);
 // Description:
diff --git a/gears.scad b/gears.scad
index 1f8c0925..ad6feef5 100644
--- a/gears.scad
+++ b/gears.scad
@@ -4519,7 +4519,7 @@ function gear_skew_angle(teeth1,teeth2,helical1,helical2,profile_shift1,profile_
 //   right(d)
 //     spur_gear2d(mod=mod,teeth=teeth2,profile_shift=ps2,shorten=shorten,gear_spin=-90,shaft_diam=5);
 //   stroke([rect([desired,40], anchor=LEFT)],color="red");
-// Example(2D,Med,NoScales,VPR=[0.00,0.00,0.00],VPD=237.09,VPT=[0.16,24.60,28.81]): The natural center distance between these gears is 32.  Using profile shifting we increase this to 34. With a ring gear and spur gear the **difference** in profile shifts must equal the computed value.  The only way to divide the profile shift is hence to place negative shift onto the spur gear, which is only acceptable for large tooth count spur gears.  It is not possible to use profile shifting to decrease the distance, because that would requires the ring gear profile shift to be less than the spur gear profile shift.  
+// Example(2D,Med,NoScales,VPR=[0.00,0.00,0.00],VPD=245,VPT=[0.16,24.60,28.81]): The natural center distance between these gears is 32.  Using profile shifting we increase this to 34. With a ring gear and spur gear the **difference** in profile shifts must equal the computed value.  The only way to divide the profile shift is hence to place negative shift onto the spur gear, which is only acceptable for large tooth count spur gears.  It is not possible to use profile shifting to decrease the distance, because that would requires the ring gear profile shift to be less than the spur gear profile shift.  
 //   teeth_ring = 57;
 //   teeth_spur = 25;
 //   mod = 2;
diff --git a/linalg.scad b/linalg.scad
index b5439eee..06c5e6c1 100644
--- a/linalg.scad
+++ b/linalg.scad
@@ -382,7 +382,7 @@ function submatrix_set(M,A,m=0,n=0) =
 //   A = hstack(M1, M2, M3)
 //   A = hstack([M1, M2, M3, ...])
 // Description:
-//   Constructs a matrix by horizontally "stacking" together compatible matrices or vectors.  Vectors are treated as columsn in the stack.
+//   Constructs a matrix by horizontally "stacking" together compatible matrices or vectors.  Vectors are treated as columns in the stack.
 //   This command is the inverse of `column`.  Note: strings given in vectors are broken apart into lists of characters.  Strings given
 //   in matrices are preserved as strings.  If you need to combine vectors of strings use {{list_to_matrix()}} as shown below to convert the
 //   vector into a column matrix.  Also note that vertical stacking can be done directly with concat.