#include <bits/stdc++.h>
using namespace std;
const long long MOD = 1e9 + 7;
const long long dy[] = {0, 0, 1, -1};
const long long dx[] = {1, -1, 0, 0};
template <class T>
void chmin(T& a, const T& b) {
  a = min(a, b);
}
template <class T>
void chmax(T& a, const T& b) {
  a = max(a, b);
}
long long H, W;
string s[51];
signed main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  cin >> H >> W;
  for (long long i = 1; i < H + 1; ++i)
    for (long long j = 1; j < W + 1; ++j) cin >> s[i][j];
  for (long long i = 1; i < H + 1; ++i)
    for (long long j = 1; j < W + 1; ++j) {
      if (s[i][j] == '#') {
        if (s[i][j + 1] == '.' && s[i][j - 1] == '.' && s[i + 1][j] == '.' &&
            s[i - 1][j] == '.') {
          cout << "No" << endl;
          return 0;
        }
      }
    }
  cout << "Yes" << endl;
  return 0;
}
