#include <bits/stdc++.h>
using namespace std;
int main() {
  char s[55][55];
  int n, m;
  cin >> n >> m;
  for (int i = 0; i < n; i++)
    for (int j = 0; j < m; j++) {
      char c;
      scanf("%c", &c);
      if (c == '#' || c == '.')
        s[i][j] = c;
      else
        j--;
    }
  bool ans = true;
  for (int i = 0; i < n; i++)
    for (int j = 0; j < m; j++)
      if (s[i][j] == '#') {
        bool k = false;
        if (i && s[i - 1][j] == '#') k = true;
        if (j && s[i][j - 1] == '#') k = true;
        if (i != n - 1 && s[i + 1][j] == '#') k = true;
        if (j != m - 1 && s[i][j + 1] == '#') k = true;
        if (!k) ans = false;
      }
  if (ans)
    printf("Yes\n");
  else
    printf("NO\n");
  return 0;
}
