#include <algorithm>
#include <cassert>
#include <cctype>
#include <climits>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstring>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <tuple>
#include <vector>
#include <list>
#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
//#define cerr if(false) cerr
#ifdef DEBUG
#define show(...) cerr << #__VA_ARGS__ << " = ", debug(__VA_ARGS__);
#else
#define show(...) 42
#endif
using namespace std;
using ll = long long;
using pii = pair<int, int>;
template <typename T, typename S>
ostream& operator<<(ostream& os, pair<T, S> a) {
    os << '(' << a.first << ',' << a.second << ')';
    return os;
}
template <typename T>
ostream& operator<<(ostream& os, vector<T> v) {
    for (auto x : v) os << x << ' ';
    return os;
}
void debug() {
    cerr << '\n';
}
template <typename H, typename... T>
void debug(H a, T... b) {
    cerr << a;
    if (sizeof...(b)) cerr << ", ";
    debug(b...);
}
int main(){
    int h, w;
    cin >> h >> w;
    vector<string>s(h);
    rep(i,h)cin >> s[i];
    int cnt = 0;
    rep(i,h)rep(j,w)cnt += s[i][j] == '#';
    if(cnt == 0){
        puts("NO");
        return 0;
    }
    for(int i = - h; i <= h; i++){
        for(int j = - w; j <= w; j++){
            vector<vector<bool>> used(h, vector<bool>(w));
            bool f = true;
            rep(x, h){
                rep(y, w){
                    if(used[x][y])continue;
                    used[x][y] = true;
                    if(s[x][y] == '#'){
                        int xx = x + i;
                        int yy = y + j;
                        if(xx < 0 or xx >= h or yy < 0 or yy >= w){
                            f = false;
                            continue;
                        }
                        if(used[xx][yy])f = false;
                        used[xx][yy] = true;
                        if(s[xx][yy] != '#'){
                            f = false;
                        }
                    }
                }
            }
            if(f){
                show(i, j);
                puts("YES");
                return 0;
            }
        }
    }
    puts("NO");
    return 0;
}