#include <bits/stdc++.h>
using namespace std;
const int N = 55;
int H, W;
const int x[] = {-1, 1, 0, 0};
const int y[] = {0, 0, -1, 1};
bool judge(int, int);
char grid[N][N];
int main() {
  int H, W;
  cin >> H >> W;
  int f = 1;
  for (int i = 0; i <= H - 1; ++i)
    for (int j = 0; j <= W - 1; ++j) cin >> grid[i][j];
  for (int i = 0; i <= H - 1; ++i)
    for (int j = 0; j <= W - 1; ++j)
      if (grid[i][j] == '#')
        if (!judge(i, j)) {
          cout << "No\n";
          f = 0;
          break;
        }
  if (f) cout << "Yes\n";
  return 0;
}
bool judge(int i, int j) {
  for (int k = 0; k <= 3; ++k) {
    if (i + x[k] >= 0 && i + x[k] < H && j + y[k] >= 0 && j + y[k] < W)
      if (grid[i + x[k]][j + y[k]] == '#') return true;
  }
  return false;
}
