#include <bits/stdc++.h>
using namespace std;
int h, w;
char c;
bool ttl;
vector<bool> num;
map<pair<int, int>, char> m;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cin >> h >> w;
  for (int i = 0; i < h; i++) {
    for (int j = 0; j < w; j++) {
      cin >> c;
      m[make_pair(i, j)] = c;
    }
  }
  for (int i = 0; i < h; i++) {
    for (int j = 0; j < w; j++) {
      ttl = true;
      if (m[make_pair(i, j)] == '#') {
        if (m[make_pair(i, j - 1)] == '.') num.push_back(false);
        if (m[make_pair(i, j - 1)] == '#') num.push_back(true);
        if (m[make_pair(i, j + 1)] == '.') num.push_back(false);
        if (m[make_pair(i, j + 1)] == '#') num.push_back(true);
        if (m[make_pair(i - 1, j)] == '.') num.push_back(false);
        if (m[make_pair(i - 1, j)] == '#') num.push_back(true);
        if (m[make_pair(i + 1, j)] == '.') num.push_back(false);
        if (m[make_pair(i + 1, j)] == '#') num.push_back(true);
        for (int k = 0; k < 4; k++) {
          ttl = false;
          if (num[k] == true) {
            ttl = true;
            break;
          }
        }
      }
      if (ttl == false) break;
    }
    if (ttl == false) break;
  }
  if (ttl == false)
    cout << "No";
  else
    cout << "Yes";
  return 0;
}
