[Gmsh] entity numbering

[quemener at isn.in2p3.fr]

Hello,

I have just started looking through the tutorial examples for GMSH, but
I have some troubles understanding how the numbering of the generated
entities is performed. For Instance in the file t2.geo:

1) Does the command "Translate {-0.05,0,0} { Point(3) ; }" generate a
point numbered by 6
and  "Translate {-0.05,0,0} { Duplicata{Point(3) ; } }" a point numbered
by 7?  Or only the
"Duplicata" command creates a new point (6 in fact) and the "simple
Translate" command
only move an existing point without creating a new one?

2) I suppose that the extrusion process creates some new points (with
assigned numbers), but how is performed the numbering for points 22, 16
and 12 mentioned in the command:
Characteristic Length{6,22,2,3,16,12}? From which points are they
extruded?

3) Similar questions for the surfaces numbered 121, 131, 135, 139, 144,
I suppose that they come from the extrusion process, but how their
numbering was decided and to which points(number) are they linked?

Thanks a lot for any help and for having written such a code which will
be of great help as soon as I shall be more used with its possibilities
(associated with GetDP).
Best regards,

                                   Gilles Quemener