#include <bits/stdc++.h>
using namespace std;
const int maxn = 55;
int a[maxn][maxn];
int main() {
  ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  ;
  int n, m;
  cin >> n >> m;
  for (int i = 0; i < n; ++i) {
    for (int j = 0; j < m; ++j) {
      char x;
      cin >> x;
      a[i][j] = x == '.';
    }
  }
  for (int i = 1; i < n - 1; ++i)
    for (int j = 1; j < m - 1; ++j)
      if (!a[i][j] && a[i][j + 1] && a[i][j - 1] && a[i + 1][j] && a[i - 1][j])
        exit(puts("No"));
  puts("Yes");
  return 0;
}
