Incorporated the changes proposed by Marc:

- Changed to code to show the menus
- Added a sentence to mention the distribution of the points

Periodic_2_triangulation_2/doc/Periodic_2_triangulation_2/Periodic_2_triangulation_2.txt

@@ -135,7 +135,7 @@ data structure, is `locally valid`
 <B>(c)</B> Any cell has its vertices ordered according to positive
 orientation. See Figure \cgalFigureRef{P2Triangulation2figorient}.
 
-# Delaunay Triangulation #
+\section P2T2_Delaunay Delaunay Triangulation
 
 The class `Periodic_2_Delaunay_triangulation_2` implements Delaunay
 triangulations of point sets in \f$ \mathbb T_c^2\f$.
@@ -150,7 +150,7 @@ four points are co-circular. Note however that the \cgal implementation computes
 This implementation is fully dynamic: it supports both insertions of
 points and vertex removal.
 
-# Triangulation Hierarchy #
+\section P2T2_Hierarchy Triangulation Hierarchy
 
 The class `Periodic_2_triangulation_hierarchy_2` is the adaptation
 of the hierarchical structure described in
@@ -372,7 +372,7 @@ requires <I>exact constructions</I>.
 
 \cgalExample{Periodic_2_triangulation_2/p2t2_geometric_access.cpp}
 
-# Design and Implementation History #
+\section P2T2_Design Design and Implementation History
 
 The periodic 2D-triangulation is based on the 2D triangulation package
 developed by Mariette Yvinec and the periodic 3D-triangulation package
@@ -383,11 +383,12 @@ developed by Manuel Caroli and Monique Teillaud. The periodic
 In 2009, Nico Kruithof started implementation of the
 `Periodic_2_triangulation_2` package.
 
-# Performance #
+\section P2T2_Performance Performance
 
 The performance of the 2D periodic Delaunay triangulation is compared
 to the Euclidean 2D Delaunay triangulation. The plot shows the running
 time in seconds for different numbers of batch inserted points. The
+points are uniformly randomly distributed in the unit rectangle. The
 tests were done on an Intel i7 @ 2.67GHz.
 
 \image html p2dt2_performance.png