#include <bits/stdc++.h>
using namespace std;
char field[100][100];
const int dx[4] = {1, 0, -1, 0};
const int dy[4] = {0, 1, 0, -1};
int main() {
  int H, W;
  cin >> H >> W;
  for (int i = 0; i < H; i++) {
    for (int j = 0; j < W; j++) {
      cin >> field[i][j];
    }
  }
  bool fflag = false;
  for (int y = 0; y < H; y++) {
    for (int x = 0; x < W; x++) {
      if (field[y][x] == '#') {
        for (int a = 0; a < 4; a++) {
          int nx = x + dx[a];
          int ny = y + dy[a];
          if (0 <= nx && nx < W && 0 <= ny && ny < H && field[ny][nx] == '#') {
            break;
          }
          if (a == 3) {
            fflag = true;
            goto end;
          }
        }
      }
    }
  }
end:
  if (fflag)
    cout << "NO" << endl;
  else
    cout << "YES" << endl;
}
