#include "bits/stdc++.h"

using namespace std;

using ll = long long;
using ld = long double;
using P = pair<int, int>;
constexpr ld EPS = 1e-12;
constexpr int INF = numeric_limits<int>::max() / 2;
constexpr int MOD = 1e9 + 7;

int main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);

    int H, W;
    cin >> H >> W;
    vector<string> s(H);
    bool check = true;
    for (int i = 0; i < H; i++)
    {
        cin >> s[i];
        for (int j = 0; j < W; j++)
            if (s[i][j] == '#')
                check = false;
    }
    if (check)
    {
        cout << "NO" << endl;
        return 0;
    }
    bool f = false;
    vector<vector<bool>> used(H, vector<bool>(W, false));
    for (int dx = 0; dx < H; dx++)
    {
        for (int dy = 0; dy < W; dy++)
        {
            if (dx == 0 && dy == 0)
                continue;
            for (int i = 0; i < H; i++)
            {
                for (int j = 0; j < W; j++)
                {
                    if (s[i][j] == '.')
                        used[i][j] = true;
                    else
                        used[i][j] = false;
                }
            }
            for (int i = 0; i < H; i++)
            {
                for (int j = 0; j < W; j++)
                {
                    if (used[i][j])
                        continue;
                    int nx = i + dx, ny = j + dy;
                    if (nx < 0 || H <= nx || ny < 0 || W <= ny)
                        continue;
                    if (used[nx][ny])
                        continue;
                    used[i][j] = used[nx][ny] = true;
                }
            }
            bool tmp = true;
            for (int i = 0; i < H; i++)
            {
                for (int j = 0; j < W; j++)
                {
                    if (!used[i][j])
                        tmp = false;
                }
            }
            if (tmp)
                f = true;
        }
    }
    for (int dx = 0; dx < H; dx++)
    {
        for (int dy = -W + 1; dy <= 0; dy++)
        {
            if (dx == 0 && dy == 0)
                continue;
            for (int i = 0; i < H; i++)
            {
                for (int j = 0; j < W; j++)
                {
                    if (s[i][j] == '.')
                        used[i][j] = true;
                    else
                        used[i][j] = false;
                }
            }
            for (int i = 0; i < H; i++)
            {
                for (int j = W - 1; j >= 0; j--)
                {
                    if (used[i][j])
                        continue;
                    int nx = i + dx, ny = j + dy;
                    if (nx < 0 || H <= nx || ny < 0 || W <= ny)
                        continue;
                    if (used[nx][ny])
                        continue;
                    used[i][j] = used[nx][ny] = true;
                }
            }
            bool tmp = true;
            for (int i = 0; i < H; i++)
            {
                for (int j = 0; j < W; j++)
                {
                    if (!used[i][j])
                        tmp = false;
                }
            }
            if (tmp)
                f = true;
        }
    }
    cout << (f ? "YES" : "NO") << endl;
}