#include <bits/stdc++.h>
using namespace std;
const int N = 1000000;
const long long mod = 1000000007;
const int dx[4] = {1, 0, -1, 0};
const int dy[4] = {0, 1, 0, -1};
long long gcd(long long A, long long B) {
  if (B == 0) return A;
  return gcd(B, A % B);
}
long long lcm(long long A, long long B) { return A * B / gcd(A, B); }
int main() {
  int h, w;
  cin >> h >> w;
  vector<string> s(h);
  for (long long int i = 0; i < h; i++) cin >> s[i];
  vector<vector<int>> grid(h, vector<int>(w));
  for (long long int i = 0; i < h; i++)
    for (long long int j = 0; j < w; j++) grid[i][j] = 0;
  for (long long int i = 0; i < h; i++) {
    for (long long int j = 0; j < w; j++) {
      for (long long int k = 0; k < 4; k++) {
        if (s[i][j] != '#') continue;
        int x = i + dx[k];
        int y = j + dy[k];
        if (x == -1 or x == w or y == -1 or y == w) continue;
        if (s[x][y] == '#') grid[i][j]++;
      }
    }
  }
  bool flag = true;
  for (long long int i = 0; i < h; i++)
    for (long long int j = 0; j < w; j++) {
      if (s[i][j] == '#' and grid[i][j] == 0) flag = false;
    }
  if (flag)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
}
