As soon as I saw a guy solving a nonogram, on his phone in Japan, I knew I was going to get into nonograms again. Nonograms are logic puzzles played on a grid using numbers as clues. This descriptions sounds a bit like Sudoku, but that's where the similarity ends.

The square grid is empty, and the clues are at the side of each row and column. Your task is to colour certain squares in the grid according the given clues. The clues are a sequence of numbers, for example 3, 4, 7 of consecutive coloured squares, separated by at least one or more empty squares. In the case of the above clue, it means that you have to colour a sequence of 3 squares, then have 1 or more blank squares, a second sequence of 4 coloured squares, white squares and a final sequence of 7 squares. Typically when the puzzle is complete a picture is formed.

These puzzles can be called many different things, amongst them: Hanjie, Paint by Numbers, Pixel Puzzles, Oekaki Logic, and Tsunami.

If you want to try out some puzzles the Sapphire Games site offers some interesting puzzles you can play online. I even managed to find a nice version of the puzzles for the Pocket PC from Conduits. The Japan Puzzle website has a good list of links for PC programs and other platforms.

With the Sudoku craze still alive and slowly evolving in a Kakuro craze, I think there's a good market for nonogram puzzle books.