def solve(table, H, W):
    def is_ok(row, col):
        if not table[row][col]:
            return True
        if row > 1 and table[row - 1][col] or row + 1 < H and table[row + 1][col]:
            return True
        if col > 1 and table[row][col - 1] or col + 1 < W and table[row][col + 1]:
            return True
        return False

    for row in range(H):
        for col in range(W):
            if not is_ok(row, col):
                return False
    return True


H, W = map(int, input().split())
table = []
for r in range(H):
    table.append(list(map(lambda x: x == "#", list(input()))))

print("Yes" if solve(table, H, W) else "No")
