Webs are ellipse-shaped nodes meant to
represent complex (=non binary) connections.
Examples are:
   Lotos multisynchronisations,
   Synchronisation vectors of automata, 
   Petri nets transitions, etc.

Webs can be connected by edges to ports or
vertice, or other webs even.

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

WARNING:not yet implemented:
Webs should stretch in a one-dimensional flat
oval shape, with user-defined length.

   Webs have default sizes and colors, as X11
resources:
  Atg*webradiushoriz
  Atg*webradiusvert
  Atg*webforeground
  Atg*webbackground