#include <bits/stdc++.h>
using namespace std;
const int N = 100005;
char s[50][50];
int h, w;
bool black(int y, int x);
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  ;
  cout << fixed << setprecision(10);
  cin >> h >> w;
  for (long long i = (long long)(0); i < (long long)(h); ++i) {
    for (long long j = (long long)(0); j < (long long)(w); ++j) {
      cin >> s[i][j];
    }
  }
  bool flg = true;
  for (long long i = (long long)(0); i < (long long)(h); ++i) {
    for (long long j = (long long)(0); j < (long long)(w); ++j) {
      if (s[i][j] == '#') {
        flg = black(i, j);
      }
    }
    if (!flg) break;
  }
  if (flg) {
    cout << "Yes"
         << "\n";
    ;
  } else {
    cout << "No"
         << "\n";
    ;
  }
  return 0;
}
bool black(int y, int x) {
  bool flg = false;
  for (int dy = -1; dy <= 1; dy += 2) {
    int ny = y + dy;
    if (0 <= ny && ny < h)
      if (s[ny][x] == '#') flg = true;
  }
  if (flg) return flg;
  for (int dx = -1; dx <= 1; dx += 2) {
    int nx = x + dx;
    if (0 <= nx && nx < w) {
      if (s[y][nx] == '#') flg = true;
    }
  }
  return flg;
}
