diff --git a/preprocess.c b/preprocess.c
index 1edf28e7..573af101 100644
--- a/preprocess.c
+++ b/preprocess.c
@@ -244,7 +244,7 @@ process_vertical_faces(int direction,
 
 static int linearindex(const int dims[3], int i, int j, int k)
 {
-    return i+dims[0]*(j+dims[1]*k);
+    return i + dims[0]*(j + dims[1]*k);
 }
 
 
@@ -379,13 +379,13 @@ static void approximate_intersection_pt(int *L, double *c, double *pt)
     double z;
 
     /* no intersection on pillars expected here! */
-    assert(L[0]!=L[2]);
-    assert(L[1]!=L[3]);
+    assert (L[0] != L[2]);
+    assert (L[1] != L[3]);
 
-    z0 = c[3*L[0]+2];
-    z1 = c[3*L[1]+2];
-    z2 = c[3*L[2]+2];
-    z3 = c[3*L[3]+2];
+    z0 = c[3*L[0] + 2];
+    z1 = c[3*L[1] + 2];
+    z2 = c[3*L[2] + 2];
+    z3 = c[3*L[3] + 2];
 
     /* find parameter a where lines L0L1 and L2L3 have same
      * z-coordinate */
@@ -404,24 +404,23 @@ static void approximate_intersection_pt(int *L, double *c, double *pt)
 
 
     /* find point (x1, y1, z) on pillar 1 */
-    b1 = (z2-z)/(z2-z0);
-    b2 = (z-z0)/(z2-z0);
-    x1 = c[3*L[0]+0]*b1 + c[3*L[2]+0]*b2;
-    y1 = c[3*L[0]+1]*b1 + c[3*L[2]+1]*b2;
+    b1 = (z2 - z) / (z2 - z0);
+    b2 = (z - z0) / (z2 - z0);
+    x1 = c[3*L[0] + 0]*b1 + c[3*L[2] + 0]*b2;
+    y1 = c[3*L[0] + 1]*b1 + c[3*L[2] + 1]*b2;
 
     /* find point (x2, y2, z) on pillar 2 */
-    b1 = (z-z3)/(z1-z3);
-    b2 = (z1-z)/(z1-z3);
-    x2 = c[3*L[1]+0]*b1 + c[3*L[3]+0]*b2;
-    y2 = c[3*L[1]+1]*b1 + c[3*L[3]+1]*b2;
+    b1 = (z - z3) / (z1 - z3);
+    b2 = (z1 - z) / (z1 - z3);
+    x2 = c[3*L[1] + 0]*b1 + c[3*L[3] + 0]*b2;
+    y2 = c[3*L[1] + 1]*b1 + c[3*L[3] + 1]*b2;
 
     /* horizontal lines are by definition ON the bilinear surface
        spanned by L0, L1, L2 and L3.  find point (x, y, z) on
        horizontal line between point (x1, y1, z) and (x2, y2, z).*/
-    pt[0] = x1* (1.0-a) + x2* a;
-    pt[1] = y1* (1.0-a) + y2* a;
+    pt[0] = x1*(1.0 - a) + x2*a;
+    pt[1] = y1*(1.0 - a) + y2*a;
     pt[2] = z;
-
 }
 
 /*-----------------------------------------------------------------