#include <bits/stdc++.h>
using namespace std;
int main() {
  int h, w;
  int han = 0;
  cin >> h >> w;
  char cam[h][w];
  for (int i = 0; i < h; i++)
    for (int j = 0; j < w; j++) cin >> cam[i][j];
  for (int i = 0; i < h; i++) {
    for (int j = 0; j < w; j++) {
      if (cam[i][j] == '#') {
        if (i == 0 && j == 0)
          if (cam[i + 1][j] != '#' && cam[i][j + 1] != '#')
            han = 1;
          else if (i == h - 1 && j == w - 1)
            if (cam[i - 1][j] != '#' && cam[i][j - 1] != '#')
              han = 1;
            else if (j == 0)
              if (cam[i + 1][j] != '#' && cam[i][j + 1] != '#' &&
                  cam[i - 1][j] != '#')
                han = 1;
              else if (i == 0)
                if (cam[i][j - 1] != '#' && cam[i + 1][j] != '#' &&
                    cam[i][j + 1] != '#')
                  han = 1;
                else if (j == w - 1)
                  if (cam[i - 1][j] != '#' && cam[i][j - 1] != '#' &&
                      cam[i + 1][j] != '#')
                    han = 1;
                  else if (i == h - 1)
                    if (cam[i - 1][j] != '#' && cam[i][j - 1] != '#' &&
                        cam[i][j + 1] != '#')
                      han = 1;
                    else if (cam[i - 1][j] != '#' && cam[i + 1][j] != '#' &&
                             cam[i][j - 1] != '#' && cam[i][j + 1] != '#')
                      han = 1;
      }
    }
    if (han == 1) {
      cout << "No" << endl;
      exit(0);
    }
  }
  if (han == 1) {
    cout << "No" << endl;
    exit(0);
  }
  cout << "Yes" << endl;
}
