A sudoku segment is a ROW of nine squares that make up a single line in a sudoku puzzle. It is composed of nine individual cells, each of which must contain a number from one to nine. The numbers in each ROW must not repeat, and the numbers in each column must also not repeat. The goal of a sudoku puzzle is to fill in all the cells with the correct numbers so that each ROW, column, and 3x3 box contains the numbers one to nine.