diff --git a/Chapter 12 2D Shape Rendering by Distance Fields/makedist/edtaa3func.c b/Chapter 12 2D Shape Rendering by Distance Fields/makedist/edtaa3func.c
index e6ca41f..9e217d5 100644
--- a/Chapter 12 2D Shape Rendering by Distance Fields/makedist/edtaa3func.c	
+++ b/Chapter 12 2D Shape Rendering by Distance Fields/makedist/edtaa3func.c	
@@ -74,7 +74,7 @@ void computegradient(double *img, int w, int h, double *gx, double *gy)
             k = i*w + j;
             if((img[k]>0.0) && (img[k]<1.0)) { // Compute gradient for edge pixels only
                 gx[k] = -img[k-w-1] - SQRT2*img[k-1] - img[k+w-1] + img[k-w+1] + SQRT2*img[k+1] + img[k+w+1];
-                gy[k] = -img[k-w-1] - SQRT2*img[k-w] - img[k+w-1] + img[k-w+1] + SQRT2*img[k+w] + img[k+w+1];
+                gy[k] = -img[k-w-1] - SQRT2*img[k-w] - img[k-w-1] + img[k+w+1] + SQRT2*img[k+w] + img[k+w+1];
                 glength = gx[k]*gx[k] + gy[k]*gy[k];
                 if(glength > 0.0) { // Avoid division by zero
                     glength = sqrt(glength);