There are actually ( 8 3 ) ( \\ displaystyle ( \\ tbinom ( 8 ) ( 3 ) ) ) = 56 combinations that satisfy the coding rules .
One would be confused with the stop symbol in reverse , and the other 7 are unused .
There are actually ( 8 3 ) ( \\ displaystyle ( \\ tbinom ( 8 ) ( 3 ) ) ) = 56 combinations that satisfy the coding rules , but one would be confused with the stop symbol in reverse , and the other 7 are unused .