#include <bits/stdc++.h>
using namespace std;
int main() {
  int h, w;
  cin >> h >> w;
  char mp[52][52];
  for (int i = 1; i <= h; i++) {
    for (int j = 1; j <= w; j++) {
      cin >> mp[i][j];
    }
  }
  int judge = 0;
  for (int i = 1; i <= h; i++) {
    for (int j = 1; j <= w; j++) {
      if (mp[i][j] == '#') {
        if (i == 1) {
          if (mp[i + 1][j] == '.' && mp[i][j + 1] == '.' &&
              mp[i][j - 1] == '.') {
            judge = 1;
          }
        } else if (i == h) {
          if (mp[i - 1][j] == '.' && mp[i][j + 1] == '.' &&
              mp[i][j - 1] == '.') {
            judge = 1;
          }
        } else if (j == 1) {
          if (mp[i + 1][j] == '.' && mp[i - 1][j] == '.' &&
              mp[i][j + 1] == '.') {
            judge = 1;
          }
        } else if (j == w) {
          if (mp[i + 1][j] == '.' && mp[i - 1][j] == '.' &&
              mp[i][j - 1] == '.') {
            judge = 1;
          }
        } else {
          if (mp[i + 1][j] == '.' && mp[i - 1][j + 1] == '.' &&
              mp[i][j + 1] == '.' && mp[i][j - 1] == '.') {
            judge = 1;
          }
        }
      }
    }
  }
  if (judge) {
    cout << "No" << endl;
  } else {
    cout << "Yes" << endl;
  }
  return 0;
}
