#include <bits/stdc++.h>
char a[100][100], n, m, i, j;
int main() {
  scanf("%d%d", &n, &m);
  for (i = 0; i <= n + 1; i++)
    for (j = 0; j <= m + 1; j++) a[i][j] = '.';
  for (i = 1; i <= n; i++) {
    scanf("%s", a[i] + 1);
    a[i][m + 1] = '.';
  }
  for (i = 1; i <= n; i++)
    for (j = 1; j <= m; j++)
      if ((a[i][j] == '#') && (a[i - 1][j] == '.') && (a[i + 1][j] == '.') &&
          (a[i][j - 1] == '.') && (a[i][j + 1] == '.')) {
        printf("No");
        return 0;
      }
  printf("Yes");
  return 0;
}
