#include <bits/stdc++.h>
using namespace std;
int main() {
  int i, j;
  int h, w;
  cin >> h >> w;
  string board[55];
  for (i = 0; i < h; i++) cin >> board[i];
  const int dx[4] = {0, 1, 0, -1};
  const int dy[4] = {-1, 0, 1, 0};
  bool can = true;
  for (i = 0; i < h; i++) {
    if (!can) break;
    for (j = 0; j < w; j++) {
      if (!can) break;
      if (board[i][j] == '.') continue;
      bool flag = false;
      for (int d = 0; d < 4; d++) {
        const int ni = i + dy[d];
        const int nj = j + dx[d];
        if (ni < 0 || h <= ni) continue;
        if (nj < 0 || w <= nj) continue;
        if (board[ni][nj] == '#') {
          flag = true;
          break;
        }
      }
      can = flag;
    }
  }
  if (can)
    cout << "YES" << endl;
  else
    cout << "NO" << endl;
  return 0;
}
