% ruby space.rb display public4.in 
----------------------------------------
Earth         Kirk McCoy Spock 
Vulcan        
----------------------------------------
Enterprise docking at Earth
----------------------------------------
Earth         Kirk McCoy Spock 
  Enterprise   
Vulcan        
----------------------------------------
Kirk boarding Enterprise at Earth
----------------------------------------
Earth         McCoy Spock 
  Enterprise   Kirk 
Vulcan        
----------------------------------------
Spock boarding Enterprise at Earth
----------------------------------------
Earth         McCoy 
  Enterprise   Kirk Spock 
Vulcan        
----------------------------------------
Enterprise departing from Earth
----------------------------------------
Earth         McCoy 
Vulcan        
----------------------------------------
Voyager docking at Earth
----------------------------------------
Earth         McCoy 
  Voyager      
Vulcan        
----------------------------------------
McCoy boarding Voyager at Earth
----------------------------------------
Earth         
  Voyager      McCoy 
Vulcan        
----------------------------------------
Enterprise docking at Vulcan
----------------------------------------
Earth         
  Voyager      McCoy 
Vulcan        
  Enterprise   Kirk Spock 
----------------------------------------
Kirk departing Enterprise at Vulcan
----------------------------------------
Earth         
  Voyager      McCoy 
Vulcan        Kirk 
  Enterprise   Spock 
----------------------------------------
Spock departing Enterprise at Vulcan
----------------------------------------
Earth         
  Voyager      McCoy 
Vulcan        Kirk Spock 
  Enterprise   
----------------------------------------
Voyager departing from Earth
----------------------------------------
Earth         
Vulcan        Kirk Spock 
  Enterprise   
----------------------------------------
Enterprise departing from Vulcan
----------------------------------------
Earth         
Vulcan        Kirk Spock 
----------------------------------------
Voyager docking at Vulcan
----------------------------------------
Earth         
Vulcan        Kirk Spock 
  Voyager      McCoy 
----------------------------------------
McCoy departing Voyager at Vulcan
----------------------------------------
Earth         
Vulcan        Kirk McCoy Spock 
  Voyager      
----------------------------------------
Enterprise docking at Earth
----------------------------------------
Earth         
  Enterprise   
Vulcan        Kirk McCoy Spock 
  Voyager      
----------------------------------------
Voyager departing from Vulcan
----------------------------------------
Earth         
  Enterprise   
Vulcan        Kirk McCoy Spock 
----------------------------------------