#include <bits/stdc++.h>
using namespace std;
int main(void) {
  int H, W;
  cin >> H >> W;
  char s[51][51];
  for (int i = 1; i <= W; i++) {
    for (int j = 1; j <= H; j++) {
      cin >> s[i][j];
    }
  }
  for (int i = 1; i <= W; i++) {
    for (int j = 1; j <= H; j++) {
      if ((s[i][j] == '#' && s[i - 1][j] == '#') ||
          (s[i][j] == 'a' && s[i - 1][j] == '#')) {
        s[i][j] = 'a';
        s[i + 1][j] = 'a';
      }
      if ((s[i][j] == '#' && s[i][j - 1] == '#') ||
          (s[i][j] == '#' && s[i][j - 1] == 'a') ||
          (s[i][j] == 'a' && s[i][j - 1] == '#')) {
        s[i][j] = 'a';
        s[i][j - 1] = 'a';
      }
    }
  }
  int ans = 0;
  for (int i = 1; i <= W; i++) {
    for (int j = 1; j <= H; j++) {
      if (s[i][j] == '#') {
        ans++;
      }
    }
  }
  if (ans == 0)
    cout << "Yes";
  else
    cout << "No";
  return 0;
}
