fetchSudokuUK: Fetch the daily sudoku puzzle from http://www.sudoku.org.uk/
Description
Fetches the daily sudoku puzzle from
http://www.sudoku.org.uk/ or one of their archive from the previous 31
days.
Usage
fetchSudokuUK(day)
Arguments
day
Optional character string specifying the day of the puzzle
to download. This is in European date format 'dd/mm/yyyy' and needs
to represent a date within the last 31 days.
Value
A 9x9 matrix representing a sudoku puzzle (blank squares have value
0).