#include <bits/stdc++.h>
using namespace std;
int getNum(vector<vector<int> > f, int x, int y, int w, int h) {
  int sum = 0;
  w--;
  h--;
  if (x != 0) sum += f[x - 1][y];
  if (x != w) sum += f[x + 1][y];
  if (y != 0) sum += f[x][y - 1];
  if (y != h) sum += f[x][y + 1];
  return sum;
}
int main(void) {
  vector<vector<int> > f;
  int w, h;
  cin >> w >> h;
  f.resize(w);
  for (int i = 0; i < h; i++) f[i].resize(h);
  char c;
  int x = 0;
  int y = 0;
  while (cin >> c) {
    if (c == '.') {
      f[x][y] = 0;
    }
    if (c == '#') {
      f[x][y] = 1;
    }
    if (x == w - 1) {
      if (y == h - 1) break;
      x = 0;
      y++;
    } else {
      x++;
    }
  }
  int check = 0;
  bool ok = false;
  for (int x = 0; x < w; x++) {
    for (int y = 0; y < h; y++) {
      if (f[x][y]) {
        check = getNum(f, x, y, w, h);
        if (check > 0)
          ok = true;
        else
          ok = false;
      } else {
      }
    }
  }
  if (ok)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
  return 0;
}
