#include <bits/stdc++.h>
using namespace std;
int H, W;
char c[55][55];
int xc[4] = {-1, 1, 0, 0};
int yc[4] = {0, 0, -1, 1};
int main() {
  ios_base::sync_with_stdio(0);
  cin >> H >> W;
  for (int i = 0; i < H; i++)
    for (int j = 0; j < W; j++) cin >> c[i][j];
  bool works = true;
  for (int i = 0; i < H; i++)
    for (int j = 0; j < W; j++) {
      if (c[i][j] == '#') {
        bool found = false;
        for (int k = 0; k < 4; k++) {
          int ni = i + xc[k], nj = j + yc[k];
          if (ni < 0 || ni >= H || nj < 0 || nj >= W) continue;
          if (c[ni][nj] == '#') found = true;
        }
        if (!found) works = false;
      }
    }
  if (works)
    cout << "YES\n";
  else
    cout << "NO\n";
  return 0;
}
