Sudoku solver — creating on-board squares

[Buwswtku]

My current university assignment is to write a sudoku solver that works with sudokus of n*m size. The language I use is java. I am currently working on constructing the squares/rectangles on the sudoku board. For 9x9 sudokus, these are the 3x3 boxes, and in ?quick sudokus? (i.e. 6x6), the 2x3 boxes.Here