#include <bits/stdc++.h>
using namespace std;
int main(void) {
  int H, W;
  cin >> H >> W;
  int field[H][W];
  for (int i = 0; i < H; i++) {
    string s;
    cin >> s;
    for (int j = 0; j < W; j++) {
      if (s.at(j) == '#') {
        field[i][j] = 1;
      } else {
        field[i][j] = 0;
      }
    }
  }
  bool can = false;
  for (int i = 0; i < H; i++) {
    for (int j = 0; j < W; j++) {
      bool flag = false;
      if (field[i][j] == 1) {
        if (i == 0) {
          if (j == 0) {
            if ((field[i + 1][j] == 1) or (field[i][j + 1] == 1)) {
              flag = true;
            } else {
              can = false;
              goto LABEL;
            }
          } else if (j == W + 1) {
            if ((field[i][j - 1] == 1) or (field[i + 1][j] == 1)) {
              flag = true;
            } else {
              can = false;
              goto LABEL;
            }
          } else {
            if ((field[i][j - 1] == 1) or (field[i + 1][j] == 1) or
                (field[i][j + 1] == 1)) {
              flag = true;
            } else {
              can = false;
              goto LABEL;
            }
          }
        } else if (i == H + 1) {
          if (j == 0) {
            if ((field[i - 1][j] == 1) or (field[i][j + 1] == 1)) {
              flag = true;
            } else {
              can = false;
              goto LABEL;
            }
          } else if (j == W + 1) {
            if ((field[i][j - 1] == 1) or (field[i - 1][j] == 1)) {
              flag = true;
            } else {
              can = false;
              goto LABEL;
            }
          } else {
            if ((field[i][j - 1] == 1) or (field[i][j + 1] == 1) or
                (field[i - 1][j] == 1)) {
              flag = true;
            } else {
              can = false;
              goto LABEL;
            }
          }
        } else {
          if (j == 0) {
            if ((field[i - 1][j] == 1) or (field[i][j + 1] == 1) or
                (field[i + 1][j] == 1)) {
              flag = true;
            } else {
              can = false;
              goto LABEL;
            }
          } else if (j == W + 1) {
            if ((field[i][j - 1] == 1) or (field[i - 1][j] == 1) or
                (field[i + 1][j] == 1)) {
              flag = true;
            } else {
              can = false;
              goto LABEL;
            }
          } else {
            if ((field[i][j - 1] == 1) or (field[i + 1][j] == 1) or
                (field[i][j + 1] == 1) or (field[i - 1][j] == 1)) {
              flag = true;
            } else {
              can = false;
              goto LABEL;
            }
          }
        }
      }
      if (flag) {
        can = true;
      }
    }
  }
LABEL:
  if (can)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
}
