#include <bits/stdc++.h>
using namespace std;
int n, m;
int dx[] = {0, 1, 0, -1};
int dy[] = {1, 0, -1, 0};
char a[55][55];
int check(int i, int j) {
  if (i <= 0 || i > n) return 0;
  if (j <= 0 || j > m) return 0;
  if (a[i][j] == '#') return 1;
  return 0;
}
int main() {
  cin >> n >> m;
  for (int i = 1; i <= n; ++i)
    for (int j = 1; j <= m; ++j) cin >> a[i][j];
  for (int i = 1; i <= n; ++i)
    for (int j = 1; j <= m; ++j) {
      int count = 0;
      for (int k = 0; k < 4; ++k) count += check(i + dx[k], j + dy[k]);
      if (!count) {
        cout << "No" << endl;
        return 0;
      }
    }
  cout << "Yes" << endl;
  return 0;
}
