void main()
{
    int[] tmp = readln.split.to!(int[]);
    int h = tmp[0], w = tmp[1];

    string[] s = new string[h];
    coord[] black;
    foreach (i; 0 .. h)
    {
        s[i] = readln.chomp;
        foreach (j, c; s[i])
        {
            if (c == '#')
            {
                black ~= coord(i, j.to!int);
            }
        }
    }

    int[] dy = [-1, 0, 1, 0], dx = [0, 1, 0, -1];
    bool ok = true;
    foreach (b; black)
    {
        bool flag;
        foreach (dir; 0 .. 4)
        {
            int y = b.y + dy[dir], x = b.x + dx[dir];
            if (y < 0 || h <= y || x < 0 || w <= x) continue;

            if (s[y][x] == '#') flag = true;
        }

        if (!flag)
        {
            ok = false;
            break;
        }
    }

    writeln(ok ? "Yes" : "No");
}

alias Tuple!(int, "y", int, "x") coord;

import std.stdio;
import std.string;
import std.array;
import std.conv;
import std.algorithm;
import std.range;
import std.math;
import std.numeric;
import std.container;
import std.typecons;
import std.ascii;
import std.uni;