#include <bits/stdc++.h>
using namespace std;
char a[100][100];
int main() {
  int r, c, n = 0, f = 0;
  cin >> r >> c;
  for (int i = 0; i <= r + 2; i++) {
    for (int j = 0; j <= c + 2; j++) {
      a[i][j] = '.';
    }
  }
  for (int i = 1; i <= r; i++) {
    for (int j = 1; j <= c; j++) {
      cin >> a[i][j];
    }
  }
  for (int i = 1; i <= r; i++) {
    for (int j = 1; j <= c; j++) {
      if (a[i][j] == '.') continue;
      if (a[i][j] == '#') {
        f = 1;
        if (a[i - 1][j] == '.' && a[i + 1][j] == '.' && a[i][j - 1] == '.' &&
            a[i][j + 1] == '.') {
          n = 1;
          break;
        }
      }
    }
    if (n == 1) break;
  }
  if (n == 0 && f == 1)
    cout << "Yes\n";
  else
    cout << "No\n";
  return 0;
}
