#include <bits/stdc++.h>
using namespace std;
const long long MOD = 1e9 + 7;
const long long INF = 1e15;
signed main() {
  long long H, W;
  cin >> H >> W;
  char A[H][W];
  for (long long i = (0); i < (H); ++i) {
    for (long long j = (0); j < (W); ++j) cin >> A[i][j];
  }
  bool ok = true;
  for (long long i = (0); i < (H); ++i) {
    for (long long j = (0); j < (W); ++j) {
      if (A[i][j] == '#' && (i - 1 == 0 || A[i - 1][j] == '.') &&
          (j - 1 == 0 || A[i][j - 1] == '.') &&
          (i + 1 == H || A[i + 1][j] == '.') &&
          (j + 1 == W || A[i][j + 1] == '.')) {
        ok = false;
      }
    }
  }
  if (H == 1 && W == 1) ok = false;
  if (ok)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
}
