#include <bits/stdc++.h>
using namespace std;
inline char gc() {
  static char buf[100000], *p1 = buf, *p2 = buf;
  return p1 == p2 && (p2 = (p1 = buf) + fread(buf, 1, 100000, stdin), p1 == p2)
             ? EOF
             : *p1++;
}
inline int read() {
  int x = 0;
  char ch = getchar();
  bool positive = 1;
  for (; !isdigit(ch); ch = getchar())
    if (ch == '-') positive = 0;
  for (; isdigit(ch); ch = getchar()) x = x * 10 + ch - '0';
  return positive ? x : -x;
}
inline void write(int x) {
  if (x < 0) x = -x, putchar('-');
  if (x > 9) write(x / 10);
  putchar(x % 10 + '0');
}
inline void writeln(int x) {
  write(x);
  puts("");
}
int n, m;
char a[100][100];
int main() {
  n = read();
  m = read();
  for (int i = 1; i <= n; i++) {
    scanf("%s", a[i] + 1);
  }
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= m; j++) {
      if (a[i][j] == '#') {
        if (a[i][j + 1] != '#' && a[i][j - 1] != '#' && a[i + 1][j] != '#' &&
            a[i - 1][j] != '#') {
          puts("NO");
          return 0;
        }
      }
    }
  }
  puts("YES");
  return 0;
}
