Sudah cuckoo

I completed my first sudoku puzzle this morning (while at work, but shhhh... don't let the boss know). After starting off on the wrong track - a colleague told me that I had to also look at the mini 3x3 squares - I completed an easy puzzle. Now I'm hooked.

What is it? It's a Japanese puzzle of a 9x9 grid in which you have to fill in the digits 1 to 9 - but you can't repeat them on the same vertical or horizontal line or within the 3x3 mini-grids. It has nothing to do with maths - just a simple logical elimination process.

When British newspapers started featuring sudoku daily, it started a craze in London among Tube commuters. I wonder if they still puzzle over them, now that many are avoiding public transport.

Check out these websites for daily printable sudokus in easy, medium and hard levels:
http://sudoku.com.au/
http://www.dailysudoku.co.uk/sudoku/index.shtml

Have fun.