import sys
H, W = map(int, input().split())
S = [input() for i in range(H)]
drawable = True


def can_draw(y, x):
    is_connected = False
    if S[y][x] == '.':
        return True

    dl = [(-1, 0), (0, 1), (1, 0), (0, -1)]
    for dy, dx in dl:
        if not(0 <= y + dy < W) or not(0 <= x + dx < H):
            continue
        if S[y + dy][x + dx] == '#':
            is_connected = True
            break
    return is_connected


for i in range(H):
    for j in range(W):
        if not can_draw(i, j):
            print('No')
            sys.exit()

print('Yes')
