#include <bits/stdc++.h>
using namespace std;
int main() {
  freopen("input.txt", "r", stdin);
  char arr[51][51];
  memset(arr, '.', sizeof arr);
  int a, b;
  cin >> a >> b;
  for (int i = 1; i <= a; i++) {
    for (int y = 1; y <= b; y++) {
      scanf(" %c", &arr[i][y]);
    }
  }
  for (int i = 1; i <= a; i++) {
    for (int y = 1; y <= b; y++) {
      if (arr[i][y] == '#') {
        if ((arr[i][y - 1] == '.') && (arr[i][y + 1] == '.') &&
            (arr[i + 1][y] == '.') && (arr[i - 1][y] == '.')) {
          cout << "No" << endl;
          return 0;
        }
      }
    }
  }
  cout << "Yes" << endl;
  return 0;
}
