#include <bits/stdc++.h>
int main() {
  int H, W;
  std::cin >> H >> W;
  char canvas[H][W];
  for (int i = 0; i <= H + 1; i++) {
    for (int j = 0; j <= W + 1; j++) {
      if (i == 0 || i == H + 1 || j == 0 || j == W + 1) {
        canvas[i][j] = 0;
      } else {
        std::cin >> canvas[i][j];
      }
    }
  }
  bool result = true;
  for (int i = 1; i <= H; i++) {
    for (int j = 1; j <= W; j++) {
      if (canvas[i][j] == '#' && canvas[i - 1][j] != '#' &&
          canvas[i + 1][j] != '#' && canvas[i][j - 1] != '#' &&
          canvas[i][j + 1] != '#') {
        result = false;
        break;
      }
    }
  }
  std::cout << (result ? "Yes" : "No") << std::endl;
  return 0;
}
