#include <bits/stdc++.h>
using namespace std;
int main() {
  int H, W;
  cin >> H >> W;
  char a;
  char vec[H][W];
  for (int k = 0; k < H; k++) {
    for (int j = 0; j < W; j++) {
      cin >> a;
      vec[k][j] = a;
    }
  }
  for (int k = 0; k < H - 1; k++) {
    for (int j = 0; j < W - 1; j++) {
      if (vec[k][j] == '#' && vec[k][j + 1] == '.' && vec[k + 1][j] == '.') {
        cout << "No" << endl;
        goto as;
      } else if (k == H - 2 && j == W - 2)
        cout << "Yes" << endl;
      else
        continue;
    }
  }
as:
  cout << endl;
}
