petri net languages

From: alex schubert (mai02iji_at_studserv.uni-leipzig.de)
Date: 04/21/04 

Date: Wed, 21 Apr 2004 10:51:23 -0700 (PDT)

hello,
i'm working on a simulator the creates petri-nets tests
whether it accepts words;
(i.e. you "draw" a net and then enter a word, and it checks
whether the word is accepted by the net)

i'm thinking about expanding the program and including
advanced properties like colored nets or something else,
and this is where i'm asking for help

has anyone an idea which more complex properties could
be useful, interesting to expand the program ?

thank you, alex