to the Coloured Sudoku puzzle.
Each square outlined in blue contains 9 small squares. Each of these
small squares must be a different colour. Also, you can't have the same
colour repeated in the same row or column of 9 squares.
To fill an empty square with a colour, first click on the colour from
the Colour Selector, then click inside the small square
in the puzzle you want to fill. The squares marked with a white cross
can't be changed.
you make a mistake, you can reset the colour to white by clicking in
the white box, then in the square you want to reset.
complicated? You'll soon get the idea. If you want to re-start, then
use the browser's 'refresh' button. Good luck. This one's really tricky.