#include <bits/stdc++.h>
using namespace std;
int main() {
  int i, j;
  int h, w;
  cin >> h >> w;
  int cnt = 0;
  char s[50][50];
  for (i = 0; i < h; i++) {
    for (j = 0; j < w; j++) {
      cin >> s[i][j];
    }
  }
  const int dx[4] = {0, 1, 0, -1};
  const int dy[4] = {-1, 0, 1, 0};
  for (i = 0; i < h; i++) {
    for (j = 0; j < w; j++) {
      if (cnt > 0) break;
      if (s[i][j] == '.') continue;
      int flag = 0;
      for (int d = 0; d < 4; d++) {
        int ni = i + dy[d];
        int nj = j + dx[d];
        if (ni < 0 || h <= ni) continue;
        if (nj < 0 || w <= nj) continue;
        if (s[ni][nj] == '#') {
          flag = 1;
          break;
        }
      }
      cnt = (1 - flag);
    }
  }
  if (cnt == 0)
    cout << "YES" << endl;
  else
    cout << "NO" << endl;
  return 0;
}
