using System;

namespace AtCoder.ABC096
{
    class c
    {
        static void Main(string[] args)
        {
            var line = Console.ReadLine().Trim();
            var spl = line.Split(' ');
            var H = int.Parse(spl[0]);
            var W = int.Parse(spl[1]);
            var campus = new char[H][];
            for(var i = 0; i < H; ++i)
            {
                line = Console.ReadLine().Trim();
                campus[i] = line.ToCharArray();
            }
            for(var i = 0; i < H; ++i)
            {
                for(var j = 0; j < W; ++j)
                {
                    if(campus[i][j] == '#')
                    {
                        if(i == 0)
                        {
                            if (j == 0)
                            {
                                if (campus[i + 1][j] == '.' && campus[i][j + 1] == '.')
                                {
                                    Console.WriteLine("No");
                                    return;
                                }
                            }
                            else if (j == W - 1)
                            {
                                if (campus[i + 1][j] == '.' && campus[i][j - 1] == '.')
                                {
                                    Console.WriteLine("No");
                                    return;
                                }
                            }
                            else
                            {
                                if (campus[i + 1][j] == '.' && campus[i][j - 1] == '.' && campus[i][j + 1] == '.')
                                {
                                    Console.WriteLine("No");
                                    return;
                                }
                            }
                        }
                        else if(i == H - 1)
                        {
                            if (j == 0)
                            {
                                if (campus[i - 1][j] == '.' && campus[i][j + 1] == '.')
                                {
                                    Console.WriteLine("No");
                                    return;
                                }
                            }
                            else if (j == W - 1)
                            {
                                if (campus[i - 1][j] == '.' && campus[i][j - 1] == '.')
                                {
                                    Console.WriteLine("No");
                                    return;
                                }
                            }
                            else
                            {
                                if (campus[i - 1][j] == '.' && campus[i][j - 1] == '.' && campus[i][j + 1] == '.')
                                {
                                    Console.WriteLine("No");
                                    return;
                                }
                            }
                        }
                        else
                        {
                            if (j == 0)
                            {
                                if (campus[i - 1][j] == '.' && campus[i + 1][j] == '.' && campus[i][j + 1] == '.')
                                {
                                    Console.WriteLine("No");
                                    return;
                                }
                            }
                            else if (j == W - 1)
                            {
                                if (campus[i - 1][j] == '.' && campus[i + 1][j] == '.' && campus[i][j - 1] == '.')
                                {
                                    Console.WriteLine("No");
                                    return;
                                }
                            }
                            else
                            {
                                if (campus[i - 1][j] == '.' && campus[i + 1][j] == '.' && campus[i][j - 1] == '.' && campus[i][j + 1] == '.')
                                {
                                    Console.WriteLine("No");
                                    return;
                                }
                            }
                        }
                    }
                }
            }
            Console.WriteLine("Yes");
        }
    }
}


Measured memory_bytes: 11220