#include <bits/stdc++.h>
using namespace std;
const int MAX_N = 60;
char a[MAX_N][MAX_N];
bool check(int i, int j) {
  bool f = true;
  if (a[i][j - 1] == '.' && a[i + 1][j] == '.' && a[i][j + 1] == '.' &&
      a[i - 1][j] == '.') {
    f = false;
  }
  return f;
}
int main() {
  int h, w;
  cin >> h >> w;
  for (int i = 1; i <= h; i++) {
    for (int j = 1; j <= w; j++) {
      cin >> a[i][j];
    }
  }
  for (int i = 1; i <= h; i++) {
    a[0][i] = '.';
    a[w + 1][i] = '.';
  }
  for (int j = 1; j <= h; j++) {
    a[j][0] = '.';
    a[j][h + 1] = '.';
  }
  int cnt = 0;
  bool ff = true;
  for (int i = 0; i < h; i++) {
    for (int j = 0; j < w; j++) {
      if (cnt) {
        if (a[i][j] == '.') {
          if (j == 1) {
            ff = check(i - 1, w);
          } else {
            ff = check(i, j - 1);
          }
        } else {
          cnt = 0;
        }
      }
      if (a[i][j] == '#') {
        cnt++;
      }
    }
  }
  if (ff == true) {
    cout << "Yes" << endl;
  } else {
    cout << "No" << endl;
  }
  return 0;
}
