规则Rules：
① 从1~9中选取6种数字，使得每行、列、宫内都是这六种数字不重复。
② 堡垒数独规则：涂色格数字大于相邻白格。
① Choose 6 different kind numbers from 1~9, to make each Row, Column or Box contains these 6 numbers.
② Rule of Fortress: The colored cells are larger than the white ones adjacent to it.
