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                                                                                                                                                                                                                  Prototype design                                                                  
                                                                                                                                                                                                                                                                                                    
                                                                                                                                                                                                                                                                                  Test prototype 0  
                                                                                                                                                                                                                                                                                                    
                                                                                                                                                                                                                                                                                  Test prototype 10 
                                                                                                                                                                                                                                                                                  Test prototype 20 
                                                                                                                                                                                                                                                                                                    
                                                                                                                                                                                                                                                                                  Test prototype 30 
                                                                                                                                                                                                                                                                                                    
                                                                                                                                                                                                                                                                                  Test prototype 40 
                                                                                                                                                                                                                                                                                  Test prototype 50 
                                                                                                                                                                                                                                                                                                    
                                                                                                                                                                                                                                                                                  Test prototype 60 
                                                                                                                                                                                                                                                                                                    
                                                                                                                                                                                                                                                                                  Test prototype 70 
                                                                                                                                                                                                                                                                                                    
                                                                                                                                                                                                                                                                                  Test prototype 80 
                                                                                                                                                                                                                                                                                  Test prototype 90 
                                                                                                                                                                                                                                                                                                    
                                                                                                                                                                                                                                                                                  Test prototype 100
                                                                                                                                                                                                                                                                                                    
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