It can also be useful for other reasons, the one that I think of is the interview question involving the knight jumping on the telephone keypad. Using the matri

It can also be useful for other reasons, the one that I think of is the interview question involving the knight jumping on the telephone keypad. Using the matrix instead of the graph, you can leverage matrix maths. Multiply the matrix by itself and miraculously you can see where the knight can go in two jumps. Use the power of 7 and sum the rows and you can count how many valid phone numbers are possible from any starting position!