The usual sudoku rules apply. Additionally, a snake has to be drawn into the grid. Head and tail of the snake are in the two cells with the gray circles. The snake may not touch itself orthogonally, but it can touch itself diagonally. The rest of the cells without the snake form exactly eight orthogonally connected areas, one of each size from 1 to 8. These areas may not touch each other orthogonally, but they can touch diagonally. Such an area of size n contains each digit from 1 to n exactly once.