#include <bits/stdc++.h>
using namespace std;
inline bool is_isolated(vector<vector<int> > vec, int i, int j, int H, int W) {
  int flag = 1;
  if (i > 1) {
    vec[i - 1][j] == 1 ? flag = 0 : 1;
  }
  if (i < H - 1) {
    vec[i + 1][j] == 1 ? flag = 0 : 1;
  }
  if (j > 1) {
    vec[i][j - 1] == 1 ? flag = 0 : 1;
  }
  if (j < W - 1) {
    vec[i][j + 1] == 1 ? flag = 0 : 1;
  }
  return flag;
}
inline int ctoi(char c) {
  if (c == '#') {
    return 1;
  } else {
    return 0;
  }
}
int main() {
  int H, W;
  cin >> H >> W;
  string ans = "Yes";
  vector<vector<int> > vec(H, vector<int>(W));
  for (int i = 0; i < H; i++) {
    for (int j = 0; j < W; j++) {
      char c;
      cin >> c;
      vec[i][j] = ctoi(c);
    }
  }
  for (int i = 0; i < H; i++) {
    for (int j = 0; j < W; j++) {
      if (vec[i][j] == 1) {
        if (is_isolated(vec, i, j, H, W)) {
          ans = "No";
        }
      }
    }
  }
  cout << ans << endl;
}
