Normal sudoku rules apply except that the regions are irregular. Additionally, a snake has to be drawn into the grid. The head and tail of the snake are in the two cells with the grey circles. The snake may not touch itself orthogonally, but it can touch itself diagonally. In the correct solution, the cells without snake form exactly eight areas, one of each size from 1 to 8. Such an area of size n contains each digit from 1 to n exactly once.