[from nikoli website]
- Place circles according to the following rules.
- Circles are permitted at any white squares. Each number indicates how many circles are next to it, vertically and horizontally.
- Each circle 'illuminates' from it to black square or outer frame in its row and column.
- Every white square must be illuminated and every circle should not illuminate each other.
It's possible to play online at http://www.puzzle-loop.com/