#include <bits/stdc++.h>
using namespace std;
const int iinf = 1 << 29;
const long long linf = 1ll << 61;
int main() {
  int m, n;
  cin >> m >> n;
  char c[m][n];
  for (int i = 0; i < m; i++) {
    for (int j = 0; j < n; j++) {
      cin >> c[i][j];
    }
  }
  for (int i = 0; i < m; i++) {
    for (int j = 0; j < n; j++) {
      if (c[i][j] == '#') {
        if (i != 0 && c[i - 1][j] == '#') continue;
        if (i != m - 2 && c[i + 1][j] == '#') continue;
        if (j != 0 && c[i][j - 1] == '#') continue;
        if (j != n - 2 && c[i][j + 1] == '#') continue;
        cout << "No" << endl;
        return 0;
      }
    }
  }
  cout << "Yes" << endl;
  return 0;
}
