#include <bits/stdc++.h>
using namespace std;
char a[51][51];
int n, h;
int main() {
  cin >> n >> h;
  for (int i = (int)0; i < (int)n; i++)
    for (int j = (int)0; j < (int)h; j++) cin >> a[i][j];
  for (int i = (int)0; i < (int)n; i++)
    for (int j = (int)0; j < (int)h; j++)
      if (a[i][j] == '#')
        if ((a[i + 1][j] != '#' || i + 1 >= n) && (a[i - 1][j] != '#' || !i) &&
            (a[i][j + 1] != '#' || j + 1 >= h) && (a[i][j - 1] != '#' || !j)) {
          cout << "NO";
          return 0;
        }
  cout << "YES";
  system("pause");
  return 0;
}
