use std::io;

fn main() {
    let mut buf = String::new();
    io::stdin().read_line(&mut buf).unwrap();
    let mut buf = buf.split_whitespace();
    let h: u32 = buf.next().unwrap().parse().unwrap();
    let w: u32 = buf.next().unwrap().parse().unwrap();

    let mut can = "Yes";

    let mut cur = String::new();
    let mut prev = String::new();
    let mut next = String::new();
    for i in 0..h {
        if i == 0 {
            cur = String::new();
            io::stdin().read_line(&mut cur).unwrap();
            cur.trim();
        }

        if i != (h - 1) {
            next = String::new();
            io::stdin().read_line(&mut next).unwrap();
            next.trim();
        }

        for j in 0..w {
            let c = match cur.chars().nth(j as usize) {
                Some(a) => a,
                None => break,
            };

            if c == '#' {
                let mut r = '.';
                let mut l = '.';
                let mut t = '.';
                let mut u = '.';
                // right
                if j != w - 1 {
                    r = match cur.chars().nth((j+1) as usize) {
                        Some(a) => a,
                        None => break,
                    };
                }
                // left
                if j != 0 {
                    l = match cur.chars().nth((j-1) as usize) {
                        Some(a) => a,
                        None => break,
                    };
                }
                // top
                if i != 0 {
                    t = match prev.chars().nth(j as usize) {
                        Some(a) => a,
                        None => break,
                    };
                }
                // under
                if i != (h - 1) {
                    u = match next.chars().nth(j as usize) {
                        Some(a) => a,
                        None => break,
                    };
                }
                if r == '.' && l == '.' && t == '.' && u == '.' {
                    can = "No";
                }
            }

            prev = cur.clone();
            cur = next.clone();
        }
    }

    println!("{}", can);
}