"kukeltje" wrote : Don't you have synchronization issues then if multiple child tokens signal the (non existing?) token to continue? This can set a counter to record the number of the coming child tokens in Join. If the coming tokens' number is equal the into Join Transitions' number, then goes on and creates a new Token.(It refers the Petrin-Net's Token , if place has the enough token then signal the transiton) View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4166291#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...