#include <bits/stdc++.h>
using namespace std;
constexpr long long mod = 1000000007;
constexpr long long INF = (1ll << 60);
constexpr double pi = 3.14159265358979323846;
template <typename T>
inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <typename T>
inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}
int main() {
  long long h, w;
  cin >> h >> w;
  vector<vector<char>> s(h, vector<char>(w));
  for (long long i = 0; i < h; ++i)
    for (long long j = 0; j < w; ++j) cin >> s[i][j];
  long long dx[4] = {0, 0, -1, 1};
  long long dy[4] = {1, -1, 0, 0};
  bool cant = false;
  for (long long i = 0; i < h; ++i) {
    for (long long j = 0; j < w; ++j) {
      bool allwhite = true;
      for (long long k = 0; k < 4; ++k) {
        long long ny = i + dy[k], nx = j + dx[k];
        if (!(0 <= ny && ny < h && 0 <= nx && nx < w)) continue;
        if (s[ny][nx] != '#') continue;
        allwhite = true;
      }
      if (allwhite) cant = true;
    }
  }
  if (cant)
    cout << "No" << endl;
  else
    cout << "Yes" << endl;
  return 0;
}
