#include <bits/stdc++.h>
using namespace std;
int di[4][2] = {{0, 1}, {-1, 0}, {0, -1}, {1, 0}};
int main(void) {
  int h, w;
  cin >> h;
  cin >> w;
  char paper[h][w];
  for (int i = 0; i < h; i++) {
    for (int j = 0; j < w; j++) {
      cin >> paper[i][j];
    }
  }
  int all = 1;
  for (int i = 0; i < h; i++) {
    for (int j = 0; j < w; j++) {
      if (paper[i][j] != '.') {
        all = 0;
        break;
      }
    }
    if (all == 0) break;
  }
  if (all == 1) {
    cout << "Yes" << endl;
    return 0;
  }
  for (int i = 0; i < h; i++) {
    for (int j = 0; j < w; j++) {
      if (paper[i][j] == '#') {
        if (j + 1 < w) {
          if (paper[i][j + 1] != '.') continue;
        }
        if (i - 1 >= 0) {
          if (paper[i - 1][j] != '.') continue;
        }
        if (j - 1 >= 0) {
          if (paper[i][j - 1] != '.') continue;
        }
        if (i + 1 < h) {
          if (paper[i + 1][j] != '.') continue;
        } else {
          cout << "No" << endl;
          return 0;
        }
      }
    }
  }
  cout << "Yes" << endl;
  return 0;
}
