import sys

input = sys.stdin.readline


class AtCoder:
    def main(self):
        H, W = map(int, input().split())
        s = [input().rstrip() for _ in range(H)]

        for i in range(H):
            s[i] = '.' + s[i] + '.'
        frame = ['.' * (W + 2)]
        s = frame + s + frame

        for h in range(1, H + 1):
            for w in range(1, W + 1):
                if s[h][w] == '#':
                    cnt = 0
                    for lr, ud in (0, -1), (0, 1), (-1, 0), (1, 0):
                        if s[h + lr][w + ud] == '#':
                            cnt += 1
                    if cnt == 0:
                        print('No')
                        exit()
        print('Yes')