#include <bits/stdc++.h>
using namespace std;
bool CanPaint(int x, int y, const vector<string> field) {
  struct Diff {
    int x;
    int y;
  };
  Diff d[4]{{1, 0}, {-1, 0}, {0, 1}, {0, -2}};
  for (int i = 0; i < 4; ++i) {
    if (x + d[i].x < 0 || x + d[i].x >= field[y].size()) continue;
    if (y + d[i].y < 0 || y + d[i].y >= field.size()) continue;
    if (field[y + d[i].y][x + d[i].x] == '#') return true;
  }
  return false;
}
int main() {
  int h, w;
  cin >> h >> w;
  vector<string> field(h);
  for (int i = 0; i < h; ++i) {
    cin >> field[i];
  }
  for (int y = 0; y < h; ++y) {
    for (int x = 0; x < w; ++x) {
      if (field[y][x] == '#' && !CanPaint(x, y, field)) {
        cout << "No" << endl;
        return 0;
      }
    }
  }
  cout << "Yes" << endl;
  return 0;
}
