#include <bits/stdc++.h>
int main() {
  int n, i, j, m, t;
  char s[50][50];
  scanf("%d%d", &n, &m);
  for (i = 0; i < n; i++) {
    for (j = 0; j < m; j++) {
      scanf("%s", &s[i][j]);
    }
  }
  for (i = 0; i < n; i++) {
    for (j = 0; j < m; j++) {
      if (s[i][j] == '#') {
        if ((s[i + 1][j] == '#') || (s[i - 1][j] == '#') ||
            (s[i][j + 1] == '#') || (s[i][j - 1] == '#'))
          t = 1;
        else
          t = 0;
      }
    }
  }
  if (t = 1)
    printf("YES");
  else
    printf("NO");
  return 0;
}
