Vertice represent (dynamic) automata states.
They are round-shaped, and could appear anywhere in
the drawing area.

   How to create a port:
- select the "edition:vertex:create" menu function;
- click with the mouse left button inside drawing
  area./ Vertice are created at button release.

A vertex has default colors, under Xresources:
  Atg*vertexforeground
  Atg*vertexbackground
and a default radius:
  Atg*vertexradius

Further vertexs attributes may alter color shades.

Vertex labels have a default fonts, as
  Atg*vertexfont

  A vertex can be made initial, and can be 
"unexplored", meaning that SOME of its outgoing
transitions are folded back (see help:explore).
Both properties are displayed as smaller inner
circles, using default colors and sizes:

  Atg*vertexinitialradius
  Atg*vertexinitialforeground
  Atg*vertexinitialbackground
  Atg*vertexexploreradius
  Atg*vertexexploreforeground
  Atg*vertexexplorebackground

  Consistency of transition edges is not assumed
before explicit completion or translation is 
required by user. See help:translation.