2 

     2 

     3 

     3 

     4 //type Pos = (Int, Int)    // a position on a chessboard 

     4 //type Pos = (Int, Int)    // a position on a chessboard 

     5 //type Path = List[Pos]    // a path...a list of positions

     5 //type Path = List[Pos]    // a path...a list of positions

     6 

     6