#include <bits/stdc++.h>
using namespace std;
int main() {
  int H, W;
  cin >> H >> W;
  vector<vector<char>> data(H, vector<char>(W));
  for (int i = 0; i < H; i++)
    for (int j = 0; j < W; j++) cin >> data.at(i).at(j);
  vector<int> dx = {1, 0, 0, -1};
  vector<int> dy = {0, 1, -1, 0};
  bool answer = true;
  for (int p = 0; p < H; p++) {
    for (int q = 0; q < W; q++) {
      if (data.at(p).at(q) == '.')
        continue;
      else {
        bool can = false;
        for (int i = 0; i < 4; i++) {
          int x = p + dx.at(i);
          int y = q + dy.at(i);
          if (x < 0 || x >= H) continue;
          if (y < 0 || y >= W) continue;
          if (data.at(x).at(y) == '#') can = true;
        }
        if (can == false) {
          answer = false;
          break;
        }
      }
    }
    if (answer = false) break;
  }
  if (answer)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
}
