#include <bits/stdc++.h>
using std::cin;
using std::cout;
using std::endl;
char can[500][500];
int main() {
  int n;
  int ans = 1;
  cin >> n;
  for (int i = 0; i <= 105; i++) {
    for (int j = 0; j <= 105; j++) {
      can[i][j] = '.';
    }
  }
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= n; j++) {
      cin >> can[i][j];
    }
  }
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= n; j++) {
      if (can[i][j] == '#' && can[i - 1][j] == '.' && can[i + 1][j] == '.' &&
          can[i][j - 1] == '.' && can[i][j + 1] == '.') {
        cout << "No";
        return 0;
      }
    }
  }
  cout << "Yes";
  return 0;
}
