if __name__ == "__main__":
    h, w = map(int, input().split())
    s = list()
    s.append('.' * (w + 2))
    for i in range(h):
        s.append('.' + input() + '.')
    s.append('.' * (w + 2))

    for i in range(h):
        for j in range(w):
            tmp = s[i+1][j] + s[i][j+1] + s[i+1][j+2] + s[i+2][j+1]
            if tmp == '....':
                print('No')
                exit()

    print('Yes')
