#include <bits/stdc++.h>
using namespace std;
const double pi =
    3.141592653589793238462643383279502884197169399375105820974944592307816406286208998628034825342;
const int mod = 1000000007;
int main() {
  int h, w;
  int flag = 0;
  char a[60][60];
  cin >> h >> w;
  for (int i = (0); i < (h); ++i) {
    for (int j = (0); j < (w); ++j) {
      a[i][j] = '.';
    }
  }
  for (int i = (0); i < (h); ++i) {
    for (int j = (0); j < (w); ++j) {
      cin >> a[i + 1][j + 1];
    }
  }
  for (int i = (0); i <= (h); ++i) {
    for (int j = (0); j <= (w); ++j) {
      if (a[i + 1][j + 1] == '#') {
        if (a[i - 1][j] == '.' && a[i + 1][j] == '. ' && a[i][j - 1] == '.' &&
            a[i][j + 1] == '.') {
          flag = 1;
        }
      }
    }
  }
  if (flag = 0)
    cout << "Yes";
  else
    cout << "No";
  return 0;
}
