#include <bits/stdc++.h>
int main() {
  int h, w, i, j, flag, flag2;
  char temp;
  int a[50][50] = {0};
  scanf("%d %d", &h, &w);
  scanf("%c", &temp);
  for (i = 0; i < h; i++) {
    for (j = 0; j < w; j++) {
      scanf("%c", &temp);
      if (temp == '#')
        a[i][j] = 1;
      else
        a[i][j] = 0;
    }
    scanf("%c", &temp);
  }
  flag2 = 0;
  for (i = 0; i < h; i++) {
    for (j = 0; j < w; j++) {
      flag = 0;
      if (a[i][j] == 0) continue;
      if (a[i][j] == 1) {
        if (a[i + 1][j] + a[i][j + 1] + a[i - 1][j] + a[i][j - 1] >= 1)
          flag = 1;
      }
      if (flag == 0) {
        flag2 = 1;
        break;
      }
    }
    if (flag2 == 1) break;
  }
  if (flag2 == 1)
    printf("No");
  else
    printf("Yes");
  return 0;
}
