#include <bits/stdc++.h>
using namespace std;
int h, w;
char s[16][16];
int dx[] = {1, 0, -1, 0}, dy[] = {0, 1, 0, -1}, rec;
int main() {
  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];
    }
  }
  for (long long i = (long long)0; i < (long long)h; i++) {
    for (long long j = (long long)0; j < (long long)w; j++) {
      rec = 0;
      if (s[i][j] == '#') {
        for (long long k = (long long)0; k < (long long)4; k++) {
          int nx = i + dx[k];
          int ny = j + dy[k];
          if (0 <= nx && nx < h && 0 <= ny && ny < w) {
            if (s[nx][ny] == '#') rec++;
          }
        }
        if (rec == 0) {
          cout << "No" << endl;
          return 0;
        }
      }
    }
  }
  cout << "Yes" << endl;
  return 0;
}
