using System;
using System.Collections.Generic;
using System.Linq;


namespace TestApp
{
    class Program
    {
        static void Main(string[] args)
        {

            var str1 = Console.ReadLine()
                .Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries)
                .Select(x => int.Parse(x))
                .ToArray();
            var isCan = true;
            var h = str1[0];
            var w = str1[1];
            var li = new bool[h+1,w+1];
            for (int i = 1; i <= h; i++)
            {
                int j = 1;
                Console.ReadLine()
                    .ToList()
                    .ForEach(x =>
                    {
                        li[i,j] = x == '#';
                        j++;
                    });
                    
            }
            for (int i = 1; i <= h; i++)
            {
                for (int j = 1; j <= w; j++)
                {
                    if (li[i, j] == true)
                    {
                        bool a, c, d, e;
                        if (i - 1 > 1)
                            a = li[i - 1, j];
                        else
                            a = false;
                        if (j - 1 > 1)
                            c = li[i, j - 1];
                        else
                            c = false;
                        if (j + 1 <= w)
                            d = li[i, j + 1];
                        else
                            d = false;
                        if (i + 1 <= h)
                            e = li[i + 1, j];
                        else
                            e = false;
                        if (!a&&!c&&!d&&!e)
                        {
                            isCan = false;
                            break;
                        }
                    }
                    
                }

            }

            if (isCan)
                Console.WriteLine("Yes");
            else
                Console.WriteLine("No");
            Console.ReadLine();

        }
    }

}