#include <bits/stdc++.h>
using namespace std;
double PI = acos(-1);
int arr[10000005];
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  cout.tie(nullptr);
  int n, m, T, res;
  int maxi = -(1 << 30) - 1, mini = (1 << 30) - 1, count = 0;
  int i, j, k;
  bool flag;
  string s1[100], s2;
  char s[100000];
  int ara[100005], ara2[100005];
  cin >> n >> m;
  for (int i = (int)(0); i <= (int)(n - 1); i++) {
    for (int j = (int)(0); j <= (int)(m - 1); j++) {
      cin >> s1[i][j];
    }
  }
  for (int i = (int)(0); i <= (int)(n - 1); i++) {
    for (int j = (int)(0); j <= (int)(m - 1); j++) {
      if (s1[i][j] == '#') {
        if (s1[i + 1][j] != '#' && s1[i][j + 1] != '#' && s1[i - 1][j] != '#' &&
            s1[i][j - 1] != '#') {
          cout << "No" << endl, exit(0);
        }
      }
    }
  }
  cout << "Yes" << endl;
}
