#include <bits/stdc++.h>
using namespace std;
int dx[4] = {1, 0, 0, -1};
int dy[4] = {0, -1, 1, 0};
int main() {
  int H, W;
  cin >> H >> W;
  vector<vector<char>> s(H, vector<char>(W));
  for (int i = 0; i < H; i++) {
    for (int j = 0; j < W; j++) {
      cin >> s[i][j];
    }
  }
  for (int i = 0; i < H; i++) {
    for (int j = 0; j < W; j++) {
      bool can = false;
      if (s[i][j] == '#') {
        for (int k = 0; k < 4; k++) {
          if (i + dx[k] >= 0 && i + dx[k] < H && j + dy[k] >= 0 &&
              j + dy[k] < W) {
            if (s[i + dx[k]][j + dy[k]] == '#') {
              can = true;
            }
          }
        }
        if (!(can)) {
          cout << "NO" << endl;
          return 0;
        }
      }
    }
  }
  cout << "YES" << endl;
  return 0;
}
