#include <bits/stdc++.h>
using namespace std;
int main() {
  int H, W;
  cin >> H >> W;
  vector<vector<char>> C(H, vector<char>(W));
  for (int i = 0; i < H; i++) {
    for (int j = 0; j < W; j++) {
      cin >> C[i][j];
    }
  }
  vector<vector<int>> memo(H + 1, vector<int>(W + 1));
  vector<int> x = {1, -1, 0, 0};
  vector<int> y = {0, 0, 1, -1};
  bool flag = true;
  for (int i = 0; i < H; i++) {
    for (int j = 0; j < W; j++) {
      if (C[i][j] == '#') {
        memo[i][j] = 1;
        int c = 0;
        for (int k = 0; k <= 3; k++) {
          if (i + x[k] < W && i + x[k] >= 0 && j + y[k] < H && j + y[k] >= 0 &&
              C[i + x[k]][j + y[k]] == '#') {
            c++;
          }
        }
        if (c == 0) flag = false;
      }
    }
  }
  int d = 0;
  for (int i = 0; i < H; i++) {
    for (int j = 0; j < W; j++) {
      if (C[i][j] == '.') {
        d++;
      }
    }
  }
  if (d == H * W) flag = false;
  if (flag)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
}
