#include <bits/stdc++.h>
using namespace std;
bool pict[55][55];
int main() {
  char a[55][55];
  int h, w;
  bool flag = true;
  cin >> h >> w;
  for (int i = 0; i < (int)(h); ++i)
    for (int j = 0; j < (int)(w); ++j) cin >> a[i + 1][j + 1];
  for (int i = 1; i < h + 1; i++) {
    for (int j = 1; j < w + 1; j++) {
      if (a[i + 1][j + 1] == '#') {
        bool flagi = false;
        if (a[i + 2][j + 1] == '#' or a[i][j + 1] == '#' or
            a[i + 1][j + 2] == '#' or a[i + 1][j] == '#')
          flagi = true;
        if (!flagi) flag = false;
      }
    }
  }
  if (flag)
    cout << "YES" << endl;
  else
    cout << "NO" << endl;
}
