using System;
using System.Text.RegularExpressions;
using System.Numerics;
using System.Linq;
using System.Collections.Generic;

namespace ConsoleApp2
{
    class Program
    {
        class ReverseComparer : IComparer<int>
        {
            public int Compare(int x, int y)
            {
                // 既定のComparerとは反対の結果を返す
                return Comparer<int>.Default.Compare(y, x);
            }
        }

        static void Main(string[] args)
        {
            
            List<int> values = new List<int>();
            string str = Console.ReadLine(); //標準入力
            //string str = "11 11";
            string[] str2 = str.Split(' ');
            int a = int.Parse(str2[0]);
            int b = int.Parse(str2[1]);

            char[,] masu = new char[a+2,b+2];

            for (int i = 0; i < b; i++)
            {
                str = Console.ReadLine();
                char[] c = str.ToCharArray();
                for (int i2 = 0; i2 < c.Length;i2++)
                {
                    masu[i+1, i2+1] = c[i2];
                }
            }

            for (int y = 1; y < b + 1; y++)
            {
                for (int x = 1; x < a + 1; x++)
                {
                    if (masu[y,x]=='#')
                    {
                        if (masu[y-1,x] != '#' && masu[y+1,x] != '#' && masu[y + 1, x] != '#' && masu[y + 1, x] != '#')
                        {
                            Console.WriteLine("No");
                            return;
                        }
                    }
                }
            }
          
            Console.WriteLine("Yes");
        }
    }
}
