#include <bits/stdc++.h>
using namespace std;
int main() {
  int h, w;
  bool res = true;
  cin >> h >> w;
  string board[50];
  int dx[4] = {0, -1, 1, 0};
  int dy[4] = {1, 0, 0, -1};
  for (int i = 0; i < h; i++) cin >> board[i];
  for (int i = 0; i < h; i++) {
    for (int j = 0; j < w; j++) {
      if (board[i][j] == '#') {
        bool can = false;
        for (int k = 0; k < 4; k++) {
          int nj = j + dx[k];
          int ni = i + dy[k];
          if ((ni >= 0 && ni < h) && (nj >= 0 && nj < w) &&
              (board[ni][nj] == '#'))
            can = true;
        }
        if (!can) res = false;
      }
    }
  }
  if (res)
    cout << "YES" << endl;
  else
    cout << "NO" << endl;
  return 0;
}
