Plan to validate:                                                                                           
                                                                                                            
Plan size: 10                                                                                               
1:                                                                                                          
(unstack b c)                                                                                               
                                                                                                            
2:                                                                                                          
(put-down b)                                                                                                
                                                                                                            
3:                                                                                                          
(unstack c d)                                                                                               
               
4:                                                                                                          
(put-down c)                                                                                                
                                                                                                            
5:                                                                                                          
(unstack d a)                                                                                               
                                                                                                            
6:                                                                                                          
(put-down d)                                                                                                
                                                                                                            
7:                                                                                                          
(pick-up a)                                                                                                 
                                                                                                            
8:                                                                                                          
(stack a c)                                                                                                 
                                                                                                            
9:                                                                                                          
(pick-up d)                                                                                                 
                                                                                                            
10:                                                                                                         
(stack d a)                                                                                                 
                                                                                                            
                                                                                                            
Plan Validation details                                                                                     
-----------------------                                                                                     
                                                                                                            
Checking next happening (time 1)                                                                            
Deleting (on b c)                                                                                           
Deleting (clear b)                                                                                          
Deleting (handempty)                                                                                        
Adding (holding b)                                                                                          
Adding (clear c)  

Checking next happening (time 2)                                                                            
Deleting (holding b)                                                                                        
Adding (clear b)                                                                                            
Adding (handempty)                                                                                          
Adding (ontable b)                                                                                          
                                                                                                            
Checking next happening (time 3)                                                                            
Deleting (on c d)                                                                                           
Deleting (clear c)                                                                                          
Deleting (handempty)                                                                                        
Adding (holding c)                                                                                          
Adding (clear d)                                                                                            
                                                                                                            
Checking next happening (time 4)                                                                            
Deleting (holding c)                                                                                        
Adding (clear c)                                                                                            
Adding (handempty)                                                                                          
Adding (ontable c)                                                                                          
                                                                                                            
Checking next happening (time 5)                                                                            
Deleting (on d a)                                                                                           
Deleting (clear d)                                                                                          
Deleting (handempty)                                                                                        
Adding (holding d)                                                                                          
Adding (clear a)                                                                                            
                                                                                                            
Checking next happening (time 6)                                                                            
Deleting (holding d)                                                                                        
Adding (clear d)                                                                                            
Adding (handempty)                                                                                          
Adding (ontable d) 

Checking next happening (time 7)
Deleting (clear a)
Deleting (ontable a)
Deleting (handempty)
Adding (holding a)

Checking next happening (time 8)
Deleting (clear c)
Deleting (holding a)
Adding (handempty)
Adding (clear a)
Adding (on a c)

Checking next happening (time 9)
Deleting (clear d)
Deleting (ontable d)
Deleting (handempty)
Adding (holding d)

Checking next happening (time 10)
Deleting (clear a)
Deleting (holding d)
Adding (handempty)
Adding (clear d)
Adding (on d a)
Plan executed successfully - checking goal
Plan valid
Final value: 10 

Successful plans:
Value: 10