#include <bits/stdc++.h>
using namespace std;
int main() {
  int H, W;
  cin >> H >> W;
  string S[H];
  for (int i = 0; i < H; ++i) {
    cin >> S[i];
  }
  const int dx[8] = {1, 0, -1, 0};
  const int dy[8] = {0, 1, 0, -1};
  int flag = 0;
  for (int i = 0; i < H; ++i) {
    for (int j = 0; j < W; ++j) {
      if (S[i][j] == '.') {
        continue;
      }
      int num = 0;
      for (int d = 0; d < 4; ++d) {
        int ni = i + dy[d];
        int nj = j + dx[d];
        if (ni < 0 or H <= ni) continue;
        if (nj < 0 or W <= nj) continue;
        if (S[ni][nj] == '#') num = 1;
      }
      if (num == 0) {
        flag = 1;
      }
    }
  }
  if (flag == 0) {
    cout << "YES" << endl;
  } else {
    cout << "NO" << endl;
  }
  return 0;
}
