#include <bits/stdc++.h>
using namespace std;
int H, W, cnt = 0;
char SG[55][55];
int main() {
  cin >> H >> W;
  for (int i = 1; i <= H; i++) {
    for (int j = 1; j <= W; j++) {
      cin >> SG[i][j];
    }
  }
  for (int i = 1; i <= H; i++) {
    for (int j = 1; j <= W; j++) {
      if (SG[i][j] == '#' && SG[i][j - 1] != '#' && SG[i - 1][j] != '#' &&
          SG[i][j + 1] != '#' && SG[i + 1][j] != '#') {
        cnt++;
      }
    }
  }
  if (cnt == 0)
    cout << "YES" << endl;
  else
    cout << "NO" << endl;
  return 0;
}
