#include <bits/stdc++.h>
using namespace std;
int main() {
  int H, W;
  cin >> H >> W;
  string line[H];
  for (int i = 0; i < H; ++i) cin >> line[i];
  string C[H + 2][W + 2];
  for (int i = 0; i < H + 2; ++i) {
    for (int j = 0; j < W + 2; ++j) C[i][j] = ".";
  }
  for (int i = 1; i <= H; ++i) {
    for (int j = 1; j <= W; ++j) C[i][j] = line[i][j];
  }
  string ans = "Yes";
  for (int i = 1; i <= H; ++i) {
    for (int j = 1; j <= W; ++j) {
      if (C[i][j] == "#" && C[i - 1][j] == "." && C[i + 1][j] == "." &&
          C[i][j - 1] == "." && C[i][j + 1] == ".")
        ans = "No";
    }
  }
  if (H == 1 && W == 1) ans = 'No';
  cout << ans << endl;
}
