#include <bits/stdc++.h>
using namespace std;
#define forx(i, a, b) for (int i = (a); i < (b); i++)
#define rep(j, n) for (int j = 0; j < (n); j++)

typedef long long ll;

int main()
{
    int h, w;
    string ans = "Yes";
    cin >> h >> w;
    char s[52][52];

    rep(i, h)
            rep(j, w){
                 cin >>s[i + 1][j + 1];
            }

            forx(i, 1, h + 1)
                forx(j, 1, w + 1) if (s[i][j] == '#' && c[i][j - 1] != '#' && s[i - 1][j] != '#' && s[i][j + 1] != '#' && s[i + 1][j] != '#')
            {
                ans == "No";
    }
    cout << ans << endl;
    return 0;
}
