#include <bits/stdc++.h>
using namespace std;
const double pi =
    3.141592653589793238462643383279502884197169399375105820974944592307816406286208998628034825342;
const int mod = 1000000007;
int main() {
  int b[111][111] = {};
  int w, h;
  int dx[4] = {1, 0, -1, 0};
  int dy[4] = {0, 1, 0, -1};
  cin >> w >> h;
  for (int i = (1); i <= (h); ++i) {
    string s;
    cin >> s;
    for (int j = (1); j <= (w); ++j) {
      if (s[j] == '#') b[i][j] = 1;
    }
  }
  for (int i = (1); i <= (h); ++i) {
    for (int j = (1); j <= (w); ++j) {
      if (!b[i][j]) continue;
      int f = 1;
      for (int d = (0); d < (4); ++d) {
        int ni = i + dx[d], nj = j + dy[d];
        if (b[ni][nj]) f = 0;
      }
      if (f) {
        cout << "No";
        return 0;
      }
    }
  }
  cout << "Yes";
  return 0;
}
