#include <bits/stdc++.h>
using namespace std;
bool inside(int i, int j, int h, int w) {
  return (i >= 0 && i < h && j >= 0 && j < w);
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int h, w;
  cin >> h >> w;
  vector<vector<char>> arr(h, vector<char>(w));
  for (int i = 0; i < h; i++)
    for (int j = 0; j < w; j++) cin >> arr[i][j];
  vector<pair<int, int>> directions{{1, 0}, {0, 1}, {-1, 0}, {0, -1}};
  for (int i = 0; i < h; i++) {
    for (int j = 0; j < w; j++) {
      if (arr[i][j] == '#') {
        bool dirCheck = false;
        for (auto dir : directions) {
          int newR = i + dir.first;
          int newC = j + dir.second;
          if (inside(newR, newC, h, w) && arr[newR][newC] == '#') {
            dirCheck = true;
            break;
          }
        }
        if (!dirCheck) {
          cout << "NO";
          return 0;
        }
      }
    }
  }
  cout << "YES";
  return 0;
}
