Space-filling Sudoku Solver

Sudoku can be solved as a space-filling. The idea is to take each digit in turn and place it in all its grid positions at once. A 4x4 solver was first developed to understand and plan the 9x9 solver. The critical concept is the collection of templates that describe the grid positions of any single digit in the completed puzzle. The templates are available in a .mat file, but can be regenerated by setting the internal variable 'saving' to 1. The programs use MATLAB nested functions and closures to provide an efficient OO implementation.