#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b;
  cin >> a >> b;
  char aa[a + 10][b + 10];
  int c = 0;
  for (int i = 0; i < a; ++i) {
    for (int j = 0; j < b; ++j) cin >> aa[i][j];
  }
  for (int m = 0; m < a; ++m) {
    for (int n = 0; n < b; ++n) {
      if (aa[m][n] == '#') {
        if ((aa[m - 1][n] == '#') && (m - 1 >= 0)) {
          aa[m][n] = 'a';
          aa[m - 1][n] = 'a';
        } else if ((aa[m + 1][n] == '#') && (m + 1 < a)) {
          aa[m][n] = 'a';
          aa[m + 1][n] = 'a';
        } else if ((aa[m][n - 1] == '#') && (n - 1 >= 0)) {
          aa[m][n] = 'a';
          aa[m][n - 1] = 'a';
        } else if ((aa[m][n + 1] == '#') && (n + 1 <= b)) {
          aa[m][n] = 'a';
          aa[m][n - 1] = 'a';
        }
      }
    }
  }
  bool res = true;
  for (int x = 0; x < a; ++x) {
    for (int y = 0; y < b; ++y) {
      if (aa[x][y] == '#') {
        res = false;
        goto fini;
      }
    }
  }
fini:
  if (res) {
    cout << "Yes" << endl;
  } else {
    cout << "No" << endl;
  }
}
