#include <bits/stdc++.h>
using namespace std;
int main() {
  int h, w;
  cin >> h >> w;
  vector<vector<char>> grid(h, vector<char>(w));
  for (int i = 0; i < (h); i++)
    for (int j = 0; j < (w); j++) cin >> grid[i][j];
  const int dx[4] = {1, 0, -1, 0};
  const int dy[4] = {0, 1, 0, -1};
  for (int i = 0; i < (h); i++)
    for (int j = 0; j < (w); j++) {
      bool ok = false;
      for (int dir = 0; dir < 4; ++dir) {
        int nh = h + dx[dir];
        int nw = w + dy[dir];
        if (nh < 0 || nh >= h || nw < 0 || nw >= w) continue;
        if (grid[nh][nw] == '#') {
          ok = true;
          continue;
        }
      }
      if (ok == false) {
        cout << "No" << endl;
        return 0;
      }
    }
  cout << "Yes" << endl;
}
