diff --git a/doc/sgpem2uman.texi b/doc/sgpem2uman.texi
index da49595..135c86a 100644
--- a/doc/sgpem2uman.texi
+++ b/doc/sgpem2uman.texi
@@ -799,11 +799,122 @@ request!
 @subsection The Simulation widget
 @cindex simulation widget
 
+@image{simulation_widget,,,Screenshot of the simulation widget}
+
+The simulation graph, as his name tell, show graphically the simulation progress
+along the time.@*
+It represent the processes status at each instant from the simulation beginning
+to the actual one.@*
+Into the graph is possible to view the processes only or both processes and threads.
+
+@strong{Note:} this graph illustrates the @emph{past}. After each simulation
+step is gone, the corresponding processes'/threads' states are drawn.
+
+The graph is divided in three areas:
+@itemize
+@item At left there are the processes (and optionally threads) names list
+@item From center to the right take place the graphical area 
+@item At the bottom there is the time ruler
+@end itemize
+
+@strong{The Processes/Threads names list}
+
+Here each process is listed in insertion order.@*
+If the thread visualization is enabled, below every process is shown a list of his threads.
+
+@strong{The graphical area}
+
+It's a rectangular region wich contains some horizontal bars.
+Each bar correspond to a process or thread; the processes' bars are fat, the threads'
+are thin.
+
+The bars are composed horizontally to show the story of each process and thread.
+If the process (thread) state change, and this is the rule, the corresponding bar
+change color.@*
+As default the colors are: green, yellow, red.
+
+@itemize
+@item @strong{Green} is used for running processes/threads
+@item @strong{Yellow} is used for ready processes/threads (waiting to run)
+@item @strong{Red} is used for blocked processes/threads (waiting for a resource)
+@end itemize
+
+The bar starts when the process or thread begin, ends when it die.@*
+The length of the bar correspond to the time life of the process or thread.
+
+
+@strong{The time ruler}
+
+Below the graphical area there is a time ruler from 0 to the current instant.@*
+The last represented time is the @emph{past} instant.
+
+The first click on play button will show only notch 0 and no process bars.@*
+At the second time, on the ruler, will be notches 0 and 1 and eventually the squares
+corresponding to living processes or threads.@*
+The other clicks... are all the same!
+
+@strong{How to show/hide threads}
+
+With the menu item "Show Threads" under the "View" menu the user can enable or
+disable threads visibility.
+
+
 @c % -------------------------------------------------
 @node The Holt graph, The Preferences dialog, The Simulation widget, From the GUI
 @subsection The Holt graph
 @cindex holt
 
+@image{holt_circle,7.3,8,Screenshot of the holt graph}
+
+The graph show the simulation status at @emph{this time}.@*
+It represent resources, processes or threads (and status),
+requests for resources and allocation.
+
+If the user choose to view processes then a circle per process is displayed,
+if she/he choose to view threads only a circle per thread (and no process)
+is displayed.
+
+Resources are drawn as squares, processes and threads are circular, requests and
+allocations are in form of arrows.@*
+An arrow from process (thread) to a resource is a request from the process to have
+the resource; an arrow from the resource to the process denote the allocation of the
+resource to the process.
+
+The colors, as usual, are: green, yellow, red.
+
+@itemize
+@item @strong{Green} is used for running processes/threads
+@item @strong{Yellow} is used for ready processes/threads (waiting to run)
+@item @strong{Red} is used for blocked processes/threads (waiting for a resource)
+@end itemize
+
+@strong{How to show processes or threads}
+
+With the menu item "Show Threads" under the "View" menu the user can switch from
+processes to threads visibility.
+
+@strong{How to show or hide the Holt Window}
+
+Holt graph, for pratical reasons, is placed in a separate frame out of the main
+application window.@*
+With the item "Show Holt graph" of the "View" menu is possible to show or hide
+this window. To close is always possible to use the standard close button or
+system menu command.
+
+@strong{Changing size and shape}
+
+The user can change size of the Holt window.@*
+As the window change size, his contents is scaled and rearranged to fit into
+the client area.@*
+If the height/width ratio is >= 5/3 the items are arranged vertially in two
+columns, resources at left, processes (or threads) at right.@*
+If the height/width ratio is <= 3/5 the items are arranged horizontally in two
+rows, resources at top, processes (or threads) at bottom.@*
+Otherwise the items are disposed along a circle.
+
+@image{holt_vert,12.1,8,Vertical arrangement of the holt graph}
+@image{holt_horiz,4.5,8,Horizontal arrangement of the holt graph}
+
 @c % -------------------------------------------------
 @node The Preferences dialog, Controlling the simulation, The Holt graph, From the GUI
 @subsection The Preferences dialog