#include <bits/stdc++.h>
int main(void) {
  int h, w, i, j, m[52][52], around, count = 0, flag = 0;
  char s[50][51];
  scanf("%d %d", &h, &w);
  for (i = 0; i < 52; i++) {
    for (j = 0; j < 52; j++) {
      m[i][j] = 0;
    }
  }
  for (i = 0; i < h; i++) {
    scanf("%s", s[i]);
    if (s[i][j] == '#') {
      m[i + 1][j + 1] = 1;
    }
  }
  for (i = 1; i < h + 1; i++) {
    for (j = 1; j < w + 1; j++) {
      around = m[i - 1][j] + m[i + 1][j] + m[i][j - 1] + m[i][j + 1];
      if ((m[i][j] == 1) && (around == 0)) {
        count = 1;
        flag = 1;
        break;
      }
    }
    if (flag == 1) {
      break;
    }
  }
  if (count == 0) {
    printf("Yes\n");
  } else {
    printf("No\n");
  }
  return 0;
}
