def possible(s):
    """Make possibility array."""
    from kaidoku.misc import box
    p = [[]] * 81
    b = box()
    for i in range(81):
        if s[i] == 0:
            p[i] = [1] * 9
            for i2 in b[i]:
                if s[i2] > 0:
                    p[i][s[i2] - 1] = 0
        else:
            p[i] = [0] * 9
            p[i][s[i] - 1] = 1
    return p
