#include <bits/stdc++.h>
using namespace std;
const int INF = 0x3f3f3f3f;
const long long LINF = 1000000000000000000;
long long n, m, l1, l2, k, sum = 0, g, num, maxn, mid;
long long d[4][2] = {1, 0, -1, 0, 0, 1, 0, -1};
char s[100][100];
int main() {
  cin >> n >> m;
  for (int i = 1; i <= n; i++) cin >> s[i] + 1;
  for (int i = 1; i <= n; i++)
    for (int j = 1; j <= m; j++) {
      g = 0;
      for (int k = 0; k <= 3; k++) {
        l1 = i + d[k][0];
        l2 = j + d[k][1];
        if (s[l1][l2] == '#') {
          g = 1;
          break;
        }
      }
      if (!g) {
        cout << "No" << endl;
        return 0;
      }
    }
  cout << "Yes" << endl;
  return 0;
}
