import sys

H, W = map(int, input().split())

rows = []
for i in range(H):
    chars = list(input())
    rows.append([1 if c == '#' else 0 for c in chars])


def is_possible(rows):
    for h in range(H):
        for w in range(W):
            if rows[h][w] == 0:
                continue

            pair_candidates = []
            if w - 1 >= 0:
                pair_candidates.append((h, w - 1))
            if w + 1 < W:
                pair_candidates.append((h, w + 1))
            if h - 1 >= 0:
                pair_candidates.append((h - 1, w))
            if h + 1 < H:
                pair_candidates.append((h + 1, w))
            pair_candidates_sum = sum([
                rows[_h][_w] for _h, _w in pair_candidates
            ])

            if pair_candidates_sum == 0:
                return False

    return True


if is_possible(rows):
    print('Yes')
else:
    print('NO')
