#include<bits/stdc++.h>
using namespace std;
int main(){
    int H, W;
    cin >> H >> W;
    string s[H];
    for(int i = 0; i < H; i++) cin >> s[i];
    int dh[] = {1, 0, -1, 0};
    int dw[] = {0, 1, 0, -1};
    for(int i = 0; i < H; i++){
        for(int j = 0; j < W; j++){
            bool po = (s[i] == '.')
            for(int k = 0; k < 4; k++){
                if(!(0 <= i + dh[k] && i + dh[k] < H && 0 <= j + dw[k] && j + dw[k] < W)) continue;
                po |= (s[i + dh[k]][j + dw[k]] == '#');
            }
            if(!po){
                cout << "No\n";
                return 0;
            }
        }
    }
    cout << "Yes\n";
    return 0;
}