H, W = map(int, input())
S = [list(input()) for __ in range(H)]

dl = [(-1, 0), (0, 1), (1, 0), (-1, -1)]
for i, row in enumerate(S):
    for j, val in enumerate(row):
        if val == '.':
            continue

        res = False
        for dx, dy in dl:
            di, dj = i + dx, j + dy
            if di < 0 or W < di or dj < 0 or H < dj:
                continue
            if S[di][dj] == '#':
                res = True
                break
        if res:
            print('No')
print('Yes')