use std::io::*;
use std::str::FromStr;

fn read<T: FromStr>() -> T {
    let stdin = stdin();
    let stdin = stdin.lock();
    let token: String = stdin
        .bytes()
        .map(|c| c.expect("failed to read char") as char)
        .skip_while(|c| c.is_whitespace())
        .take_while(|c| !c.is_whitespace())
        .collect();
    token.parse().ok().expect("failed to parse token")
}

fn main() {
    const TARGET: char = '#';
    let h: u32 = read();
    let w: u32 = read();
    let mut board: Vec<Vec<char>> = (0..h).map(|_| read::<String>().chars().collect()).collect();
    let mut ans = "YES";
    for y in 0..h {
        for x in 0..w {
            if board[y as usize][x as usize] == TARGET {
                if ((y > 0 && board[(y as usize) - 1][x as usize] != TARGET)
                    && (y < h - 1 && board[(y as usize) + 1][x as usize] != TARGET)
                    && (x > 0 && board[y as usize][(x as usize) - 1] != TARGET)
                    && (x < w - 1 && board[y as usize][(x as usize) + 1] != TARGET))
                {
                    ans = "NO";
                }
            }
        }
    }
    println!("{}", ans)
}
