[From string (line 22) ]                                                      
                                                                              
@startuml                                                                     
hide empty description                                                        
                                                                              
state Active {                                                                
                                                                              
state Producer {                                                              
 state P1                                                                     
 state fork1   <<fork>>                                                       
 state P2                                                                     
 [*] --> P1                                                                   
}                                                                             
                                                                              
state choice1 <<choice>>                                                      
--                                                                            
state Consumer {                                                              
 state C1                                                                     
 state C2                                                                     
 state fork2   <<fork>>                                                       
 [*] --> C1                                                                   
}                                                                             
                                                                              
P1 --> fork1                                                                  
^^^^^                                                                         
 The state P1 has been created in a concurrent state : it cannot be used here.