diff --git a/rtree.c b/rtree.c
index d0bd6df..7830d42 100644
--- a/rtree.c
+++ b/rtree.c
@@ -12,43 +12,43 @@
 #define RIGHT_ANGLE  (22.0)
 #define RIGHT_SIZE   (0.70)
 
-void tree (int level, double len);
+void tree(const int level, const double len);
 
 double Left_angle;
 double Right_angle;
 double Left_size;
 double Right_size;
 
-int main (int argc, const char *argv[])
+int main(int argc, const char *argv[])
 {
-   int level = 8;
-   double size = 65.0;  /* 65mm trunk for A3 */
+   const int level = 8;
+   const double size = 65.0;  /* 65mm trunk for A3 */
    
-   turtle (DEV_HPGL, SIZ_A3, ORI_LAND, FLG_BORD|FLG_RELS);
+   turtle(DEV_HPGL, SIZ_A3, ORI_LAND, FLG_BORD|FLG_RELS);
    
-// title ("http://www.dorkbot.org/dorkbotbristol/", 3.75, BOT|LEFT, FLG_NONE);
-   title ("Bristol Hackspace", 3.75, BOT|LEFT, FLG_NONE);
-   title ("2018-04-22", 3.75, BOT|RIGHT, FLG_NONE);
+// title("http://www.dorkbot.org/dorkbotbristol/", 3.75, BOT|LEFT, FLG_NONE);
+   title("Bristol Hackspace", 3.75, BOT|LEFT, FLG_NONE);
+   title("2018-04-22", 3.75, BOT|RIGHT, FLG_NONE);
    
-   srand ((unsigned int)time (NULL));
+   srand((unsigned int)time(NULL));
 
-   Left_angle = LEFT_ANGLE + (((double)rand () / (double)RAND_MAX) * 6.0);
-   Right_angle = RIGHT_ANGLE + (((double)rand () / (double)RAND_MAX) * 6.0);
+   Left_angle = LEFT_ANGLE + (((double)rand() / (double)RAND_MAX) * 6.0);
+   Right_angle = RIGHT_ANGLE + (((double)rand() / (double)RAND_MAX) * 6.0);
    
-   Left_size = LEFT_SIZE + (((double)rand () / (double)RAND_MAX) * 0.05);
-   Right_size = RIGHT_SIZE + (((double)rand () / (double)RAND_MAX) * 0.05);
+   Left_size = LEFT_SIZE + (((double)rand() / (double)RAND_MAX) * 0.05);
+   Right_size = RIGHT_SIZE + (((double)rand() / (double)RAND_MAX) * 0.05);
    
-   pen (UP);
-   turn (-90.0);
-   forward (1.9 * size);
-   turn (180.0);
-   pen (DOWN);
+   pen(UP);
+   turn(-90.0);
+   forward(1.9 * size);
+   turn(180.0);
+   pen(DOWN);
 
-   colour (BLACK);
+   colour(BLACK);
    
-   tree (level, size);
+   tree(level, size);
 
-   show ();
+   show();
    
    return (0);
 }
@@ -56,20 +56,20 @@ int main (int argc, const char *argv[])
 
 /* tree --- recursive function to plot a tree */
 
-void tree (int level, double len)
+void tree(const int level, const double len)
 {
-   forward (len);
+   forward(len);
 
    if (level == 0) {
-      turn (180.0);
+      turn(180.0);
    }
    else {
-      turn (Left_angle);
-      tree (level - 1, len * Left_size);
-      turn ((180.0 - Left_angle) - Right_angle);
-      tree (level - 1, len * Right_size);
-      turn (Right_angle);
+      turn(Left_angle);
+      tree(level - 1, len * Left_size);
+      turn((180.0 - Left_angle) - Right_angle);
+      tree(level - 1, len * Right_size);
+      turn(Right_angle);
    }
 
-   forward (len);
+   forward(len);
 }
diff --git a/tree.c b/tree.c
index 47ea302..7343250 100644
--- a/tree.c
+++ b/tree.c
@@ -10,30 +10,30 @@
 #define RIGHT_ANGLE  (25.0)
 #define RIGHT_SIZE   (0.75)
 
-void tree (int level, double len);
+void tree(const int level, const double len);
 
-int main (int argc, const char *argv[])
+int main(int argc, const char *argv[])
 {
-   int level = 8;
-// double size = 30.0;  /* 30mm trunk for A4 */
-   double size = 65.0;  /* 65mm trunk for A3 */
+   const int level = 8;
+// const double size = 30.0;  /* 30mm trunk for A4 */
+   const double size = 65.0;  /* 65mm trunk for A3 */
    
-   turtle (DEV_HPGL, SIZ_A1, ORI_LAND, FLG_NONE|FLG_RELS|FLG_BORD);
+   turtle(DEV_HPGL, SIZ_A1, ORI_LAND, FLG_NONE|FLG_RELS|FLG_BORD);
    
-// title ("http://www.dorkbot.org/dorkbotbristol/", 3.75, BOT|CENTRE, FLG_NONE);
-   title ("Bristol Hackspace", 3.75, BOT|CENTRE, FLG_NONE);
+// title("http://www.dorkbot.org/dorkbotbristol/", 3.75, BOT|CENTRE, FLG_NONE);
+   title("Bristol Hackspace", 3.75, BOT|CENTRE, FLG_NONE);
    
-   pen (UP);
-   turn (-90.0);
-   forward (1.9 * size);
-   turn (180.0);
-   pen (DOWN);
+   pen(UP);
+   turn(-90.0);
+   forward(1.9 * size);
+   turn(180.0);
+   pen(DOWN);
 
-   colour (BLACK);
+   colour(BLACK);
    
-   tree (level, size);
+   tree(level, size);
 
-   show ();
+   show();
    
    return (0);
 }
@@ -41,20 +41,20 @@ int main (int argc, const char *argv[])
 
 /* tree --- recursive function to plot a tree */
 
-void tree (int level, double len)
+void tree(const int level, const double len)
 {
-   forward (len);
+   forward(len);
 
    if (level == 0) {
-      turn (180.0);
+      turn(180.0);
    }
    else {
-      turn (LEFT_ANGLE);
-      tree (level - 1, len * LEFT_SIZE);
-      turn ((180.0 - LEFT_ANGLE) - RIGHT_ANGLE);
-      tree (level - 1, len * RIGHT_SIZE);
-      turn (RIGHT_ANGLE);
+      turn(LEFT_ANGLE);
+      tree(level - 1, len * LEFT_SIZE);
+      turn((180.0 - LEFT_ANGLE) - RIGHT_ANGLE);
+      tree(level - 1, len * RIGHT_SIZE);
+      turn(RIGHT_ANGLE);
    }
 
-   forward (len);
+   forward(len);
 }