using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp20
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] HW = Console.ReadLine().Split().Select(int.Parse).ToArray();
            string[] S = new string[HW[0]];
            string ans = "Yes";
            for (int i = 0; i < HW[0]; i++)
            {
                S[i] = Console.ReadLine();
            }
            for (int i = 0; i < S.Length; i++)
            {
                S[i] = "." + S[i] + ".";
            }
            for (int i = 1; i < S[0].Length-1; i++)
            {
                if (S[0][i] == '#')
                {
                    if (S[0][i - 1] == '.' && S[0][i + 1] == '.' && S[1][i] == '.') ans = "No";
                }
            }
            for (int i = 1; i < HW[0] - 1; i++)
            {
                for (int j = 1; j < S[i].Length - 1; j++)
                {
                    if (S[i][j] == '#')
                    {
                        if (S[i][j - 1] == '.' && S[i][j + 1] == '.' && S[i + 1][j] == '.' && S[i - 1][j] == '.') ans = "No";
                    }
                }
            }
            for (int i = 1; i < S.Length-1; i++)
            {
                if (S[HW[0] - 1][i] == '#')
                {
                    if (S[HW[0] - 1][i - 1] == '.' && S[HW[0] - 1][i + 1] == '.' && S[HW[0] - 2][i] == '.') ans = "No";
                }
            }
            Console.WriteLine(ans);
        }
    }
}
