#include <bits/stdc++.h>
using namespace std;
int main() {
  int H, W;
  cin >> H >> W;
  char X[H + 2][W + 2];
  bool x = true;
  for (int i = 0; i < H + 2; i++) {
    X[i][0] = '.';
    X[i][W + 1] = '.';
  }
  for (int i = 0; i < W + 2; i++) {
    X[0][i] = '.';
    X[H + 1][i] = '.';
  }
  for (int i = 1; i <= H; i++)
    for (int j = 0; j <= W; j++) cin >> X[i][j];
  for (int i = 1; i <= H; i++)
    for (int j = 0; j <= W; j++)
      if (X[i][j] == '#' && X[i - 1][j] == '.' && X[i + 1][j] == '.' &&
          X[i][j - 1] == '.' && X[i][j + 1] == '.')
        x = false;
  if (x)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
}
