--- a/scripts/plot/ribbon.m
+++ b/scripts/plot/ribbon.m
@@ -31,9 +31,11 @@
 
 ## Author: Kai Habel <kai.habel at gmx.de>
 
-function h = ribbon (x, y, width)
+function h = ribbon (x, y, width = 0.75)
 
-  newplot ();
+  if (nargin < 1 || nargin > 3)
+    print_usage ();
+  endif
 
   if (nargin == 1)
     y = x;
@@ -42,46 +44,42 @@
     endif
     [nr, nc] = size (y);
     x = repmat ((1:nr)', 1, nc);
-    width = 0.75;
-  elseif (nargin == 2)
-    width = 0.75;
-  elseif (nargin != 3)
-    print_usage ();
   endif
 
   if (isvector (x) && isvector (y))
     if (length (x) != length (y))
-      error ("ribbon: in case of vectors, X and Y must have same length");
+      error ("ribbon: vectors X and Y must have the same length");
     else
       [x, y] = meshgrid (x, y);
     endif
   else
-    if (! size_equal(x, y))
-      error ("ribbon: in case of matrices, X and Y must have same size");
+    if (! size_equal (x, y))
+      error ("ribbon: matrices X and Y must have the same size");
     endif
   endif
 
+  newplot ();
+
   [nr, nc] = size (y);
-  tmp = zeros (1, nc);
+  htmp = zeros (nc, 1);
 
   for c = nc:-1:1
     zz = [y(:,c), y(:,c)];
     yy = x(:,c);
     xx = [c - width / 2, c + width / 2];
     [xx, yy] = meshgrid (xx, yy);
-    cc = ones (size (zz)) * c;
-    tmp(c) = surface (xx, yy, zz, cc);
+    cc = repmat (c, size (zz));
+    htmp(c) = surface (xx, yy, zz, cc);
   endfor
 
-  ax = get (tmp(c), "parent");
-
   if (! ishold ())
-    set (ax, "view", [-37.5, 30], "box", "off", "xgrid", "on",
-         "ygrid", "on", "zgrid", "on");
+    ax = get (htmp(1), "parent");
+    set (ax, "view", [-37.5, 30], "box", "off", 
+             "xgrid", "on", "ygrid", "on", "zgrid", "on");
   endif
 
   if (nargout > 0)
-    h = tmp;
+    h = htmp;
   endif
 
 endfunction
@@ -93,3 +91,4 @@
 %! [x, y] = meshgrid (x, y);
 %! ribbon (y, z);
 
+%!FIXME: Could have some input validation tests here