#include<bits/stdc++.h>
using namespace std;

template<typename T>
bool chmax(T &a, const T &b){
    if (a >= b){
        return false;
    }
    a = b;
    return true;
}
template<typename T>
bool chmin(T &a, const T &b){
    if (a <= b){
        return false;
    }
    a = b;
    return true;
}

vector<vector<int>> max_ur(vector<vector<char>> &a){
    int h = a.size();
    int w = a[0].size();
    vector<vector<int>> ans(h,vector<int>(w,0));
    for (int i = 0; i < h; i++) for (int j = 0; j < w; j++){
        if (a[i][j] == '#'){
            ans[i][j] = 1;
            if (i > 0 && j > 0){
                chmax(ans[i][j],ans[i-1][j-1]+1);
            }
        }
    }
    return ans;
}

template<typename T>
void rotated(vector<vector<T>> &a){
    int h = a.size();
    int w = a[0].size();
    vector<vector<T>> b(w,vector<T>(h));
    for (int i = 0; i < h; i++) for (int j = 0; j < w; j++){
        b[j][h-1-i] = a[i][j];
    }
    swap(a,b);
}

int main(){
    int h, w; cin >> h >> w;
    vector<vector<char>> a(h,vector<char>(w));
    for (int i = 0; i < h; i++) for (int j = 0; j < w; j++){
        cin >> a[i][j];
    }
    vector<vector<int>> dp(h,vector<int>(w,h+w));
    for (int t = 0; t < 4; t++){
        auto ep = max_ur(a);
        for (int s = 0; s < 4-t; s++){
            rotated(ep);
        }
        for (int i = 0; i < h; i++) for (int j = 0; j < w; j++){
            chmin(dp[i][j],ep[i][j]);
        }
        rotated(a);
    }
    vector<vector<int>> imosm(h,vector<int>(w,0)), imosp(h,vector<int>(w,0));
    for (int i = 0; i < h; i++) for (int j = 0; j < w; j++){
        if (dp[i][j] <= 1) continue;
        int r = dp[i][j]-1;
        imosm[i-r][j-r]++;
        if (i+r+1 < h && j+r+1 < w){
            imosm[i+r+1][j+r+1]--;
        }
        imosp[i-r][j+r]++;
        if (i+r+1 < h && j-r-1 >= 0){
            imosp[i+r+1][j-r-1]--;
        }
    }
    for (int i = 0; i < h; i++) for (int j = 0; j < w; j++){
        if (i+1 < h && j+1 < w){
            imosm[i+1][j+1] += imosm[i][j];
        }
        if (i+1 < h && j-1 >= 0){
            imosp[i+1][j-1] += imosp[i][j];
        }
    }
    bool ans = true;
    for (int i = 0; i < h; i++) for (int j = 0; j < w; j++){
        if (a[i][j] == '#' && imosm[i][j]+imosp[i][j] == 0){
            ans = false;
            break;
        }
    }
    cout << (ans ? "Yes" : "No") << endl;
}