diff --git a/doc/texinfo/gmsh.texi b/doc/texinfo/gmsh.texi
index a74cb5407ef476c54a514cdf4459444664675c1a..4d4488ce1ad8936c47a89d23c506682d0b9b45b1 100644
--- a/doc/texinfo/gmsh.texi
+++ b/doc/texinfo/gmsh.texi
@@ -1,5 +1,5 @@
 \input texinfo.tex @c -*-texinfo-*-
-@c $Id: gmsh.texi,v 1.123 2004-07-02 02:40:47 geuzaine Exp $
+@c $Id: gmsh.texi,v 1.124 2004-07-02 15:59:06 geuzaine Exp $
 @c
 @c Copyright (C) 1997-2004 C. Geuzaine, J.-F. Remacle
 @c
@@ -1944,19 +1944,23 @@ extruded and has the following syntax:
 @example
 @var{layers}:
 @group
-  Layers @{ @{ @var{expression-list} @}, @{ @var{expression-list} @}, 
-           @{ @var{expression-list} @} @}; | Recombine;
+  Layers @{ @{ @var{expression-list} @}, < @{ @var{expression-list} @}, >
+           @{ @var{expression-list} @} @}; | Recombine; |
 @end group
 @end example
 
 The first @var{expression-list} defines how many elements should be created
-in each extruded layer. The second @var{expression-list} assigns a region
-number to each layer, which, if non-zero, overrides the elementary entity
-number of the extruded entity. This is useful when there is more than one
-layer, as the elements in each layer can then be identified in a unique
-way. The last @var{expression-list} gives the normalized height of each
-layer (the list should contain a sequence of @var{n} numbers 0 < @var{h1} <
-@var{h2} < @dots{} < @var{hn} <= 1). See @ref{t3.geo}, for an example.
+in each extruded layer. The (optional) second @var{expression-list} assigns
+a region number to each layer, which, if non-zero, overrides the elementary
+entity number of the extruded entity.  This is useful when there is more
+than one layer, as the elements in each layer can then be identified in a
+unique way.  If the region number is set to zero, or if the
+@var{expression-list} is omitted, the elements are associated with the
+automatically created elementary geometrical entity (line, surface or
+volume) created during the extrusion. The last @var{expression-list} gives
+the normalized height of each layer (the list should contain a sequence of
+@var{n} numbers 0 < @var{h1} < @var{h2} < @dots{} < @var{hn} <= 1). See
+@ref{t3.geo}, for an example.
 
 For line extrusions, the @code{Recombine} option will recombine triangles
 into quadrangles when possible.  For surface extrusions, the
diff --git a/tutorial/t3.geo b/tutorial/t3.geo
index 6dc98813393020aec7b5e656a38a3426ebec4f8b..b33f336ef2ffbdbadf80e6a38d441cc05bb5879f 100644
--- a/tutorial/t3.geo
+++ b/tutorial/t3.geo
@@ -37,10 +37,11 @@ Extrude Surface { 122, {0,1,0} , {-0.1,0,0.1} , -Pi/2 } {
 // {0,0.15,0.25}, Pi/2) can also be combined:
 
 aa[] = Extrude Surface {news-1, {-2*h,0,0}, {1,0,0} , {0,0.15,0.25} , Pi/2}{ 
-  Layers {10,0,1}; Recombine; 
+  Layers { 10, 1 }; Recombine; 
 }; ;
 
-// In this last extrusion command, we set the volume number to 0,
+// In this last extrusion command we didn't specify an explicit
+// volume number (which is equivalent to setting it to "0"),
 // which means that the elements will simply belong the automatically
 // created volume (whose number we get from the aa[] list).