using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Text;
using static System.Console;
using static System.Math;

namespace Atcoder
{
    class Program
    {
        static StreamWriter sw = new StreamWriter(OpenStandardOutput()) { AutoFlush = false };
        static void Main(string[] args)
        {
            try
            {
                SetOut(sw);
                Solve.Answer();
                Out.Flush();
            }
            catch (Exception ex)
            {
                WriteLine(ex.ToString());
            }
        }
    }

    public class Solve
    {
        public static void Answer()
        {
            var hw = IO.RSInt;
            string[] map = new string[hw[0]];
            for (int i = 0; i < hw[0]; i++)
            {
                map[i] = ReadLine();
            }
            // 上下左右の差分ベクトル
            int[] dx = new int[] { -1, 0, 1, 0 };
            int[] dy = new int[] { 0, -1, 0, 1 };
            for (int i = 0; i < hw[0]; i++)
            {
                for (int j = 0; j < hw[1]; j++)
                {
                    bool ok = false;
                    for (int k = 0; k < 4; k++)
                    {
                        if (map[i][j] == '#')
                        {
                            //移動できるマスに"#"があればOK！
                            if (0 <= i + dy[k] && i + dy[k] < hw[0] && 0 <= j + dx[k] && j + dx[k] < hw[1] && map[i + dy[k]][j + dx[k]] == '#')
                            {
                                ok = true;
                            }
                        }
                        else
                        {
                            ok = true;
                        }
                    }
                    if (!ok)
                    {
                        WriteLine("No");
                        return;
                    }
                }
            }
            WriteLine("Yes");
        }
    }

    public class IO
    {
        #region Input
        public static int RInt => int.Parse(ReadLine());
        public static long RLong => long.Parse(ReadLine());
        public static double RDouble => double.Parse(ReadLine());

        public static string[] RSString => ReadLine().Split();
        public static int[] RSInt => ReadLine().Split().Select(s => int.Parse(s)).ToArray();
        public static long[] RSLong => ReadLine().Split().Select(s => long.Parse(s)).ToArray();
        public static double[] RSDouble => ReadLine().Split().Select(s => double.Parse(s)).ToArray();
        #endregion

        #region Output
        public static void OutJoinSpace<T>(IEnumerable<T> list) => WriteLine(string.Join(" ", list));
        public static void WriteLineYes_or_No(bool flag) => WriteLine(flag ? "Yes" : "No");
        public static void WriteLineYES_or_NO(bool flag) => WriteLine(flag ? "YES" : "NO");
        #endregion
    }

    public class Mod
    {
        #region
        private readonly static long M = 1000000007;

        public static long Add(long a, long b) => (a * b) % M;
        public static long Sub(long a, long b) => (a - b) % M >= 0 ? (a - b) % M : (a - b) % M + M;
        public static long Multi(long a, long b) => (a * b) % M;
        #endregion
    }
}

Measured memory_bytes: 13396