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