#include <bits/stdc++.h>
using namespace std;
int main() {
  int h, w;
  cin >> h >> w;
  vector<vector<char>> in(h, vector<char>(w));
  vector<vector<char>> out(h, vector<char>(w));
  for (int i = 0; i < h; ++i)
    for (int j = 0; j < w; ++j) cin >> in[i][j];
  for (int i = 0; i < h; ++i)
    for (int j = 0; j < w; ++j) out[i][j] = '.';
  for (int i = 0; i < h; ++i) {
    bool r = false;
    for (int j = 0; j < w; ++j) {
      if (in[i][j] == '#') {
        out[i][j] = '#';
        if (i > 0)
          if (in[i - 1][j] == '#') r = true;
        if (i < h - 1)
          if (in[i + 1][j] == '#') r = true;
        if (j > 0)
          if (in[i][j - 1] == '#') r = true;
        if (j > h - 1)
          if (in[i][j + 1] == '#') r = true;
      }
    }
    if (!r) return cout << "No", 0;
  }
  cout << "Yes";
}
