--- a/scripts/image/prism.m	Tue Dec 28 20:46:17 2010 +0100
+++ b/scripts/image/prism.m	Tue Dec 28 13:08:23 2010 -0800
@@ -17,21 +17,23 @@
 ## <http://www.gnu.org/licenses/>.
 
 ## -*- texinfo -*-
-## @deftypefn {Function File} {} prism (@var{n})
-## Create color colormap.  This colormap cycles trough red, orange, yellow,
-## green, blue and violet.  The argument @var{n} should be a scalar.  If it
-## is omitted, the length of the current colormap or 64 is assumed.
+## @deftypefn  {Function File} {@var{map} =} prism ()
+## @deftypefnx {Function File} {@var{map} =} prism (@var{n})
+## Create color colormap.  This colormap cycles through red, orange, yellow,
+## green, blue and violet with each index change.
+## The argument @var{n} must be a scalar.  
+## If unspecified, the length of the current colormap, or 64, is used.
 ## @seealso{colormap}
 ## @end deftypefn
 
 ## Author:  Kai Habel <kai.habel@gmx.de>
 
-function map = prism (number)
+function map = prism (n)
 
   if (nargin == 0)
-    number = rows (colormap);
+    n = rows (colormap);
   elseif (nargin == 1)
-    if (! isscalar (number))
+    if (! isscalar (n))
       error ("prism: argument must be a scalar");
     endif
   else
@@ -40,10 +42,10 @@
 
   p = [1, 0, 0; 1, 1/2, 0; 1, 1, 0; 0, 1, 0; 0, 0, 1; 2/3, 0, 1];
 
-  if (rem (number, 6) == 0)
-    map = kron(ones (fix (number / 6), 1), p);
+  if (rem (n, 6) == 0)
+    map = kron(ones (fix (n / 6), 1), p);
   else
-    map = [kron(ones (fix (number / 6), 1), p); p(1:rem (number, 6), :)];
+    map = [kron(ones (fix (n / 6), 1), p); p(1:rem (n, 6), :)];
   endif
 
 endfunction
@@ -52,5 +54,5 @@
 %! ## Show the 'prism' colormap as an image
 %! image (1:64, linspace (0, 1, 64), repmat (1:64, 64, 1)')
 %! axis ([1, 64, 0, 1], "ticy", "xy")
-%! colormap prism
+%! colormap (prism (64))