#include <bits/stdc++.h>
using namespace std;
int main() {
  int H, W;
  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];
    }
  }
  bool info = true;
  for (int i = 1; i < H - 1; ++i) {
    for (int j = 1; j < W - 1; ++j) {
      if (S[i][j] == '#') {
        if (S[i][j + 1] == '#')
          info = true;
        else if (S[i][j - 1] == '#')
          info = true;
        else if (S[i + 1][j] == '#')
          info = true;
        else if (S[i - 1][j] == '#')
          info = true;
        else
          info = false;
      }
      if (!info) break;
    }
    if (!info) break;
  }
  for (int i = 1; i < H - 1; ++i) {
    for (int j : {0, W - 1}) {
      if (S[i][j] == '#') {
        if (S[i + 1][j] == '#')
          info = true;
        else if (S[i - 1][j] == '#')
          info = true;
        else if (j == 0 && S[i][1] == '#')
          info = true;
        else if (j == W - 1 && S[i][W - 2] == '#')
          info = true;
        else
          info = false;
      }
    }
  }
  for (int j = 1; j < W - 1; ++j) {
    for (int i : {0, H - 1}) {
      if (S[i][j] == '#') {
        if (S[i][j + 1] == '#')
          info = true;
        else if (S[i][j - 1] == '#')
          info = true;
        else if (i == 0 && S[1][j] == '#')
          info = true;
        else if (i == H - 1 && S[H - 2][j] == '#')
          info = true;
        else
          info = false;
      }
    }
  }
  if (S[0][0] == '#') (S[0][1] == '#') ? info = true : info = false;
  if (S[0][0] == '#') (S[1][0] == '#') ? info = true : info = false;
  if (S[H - 1][0] == '#') (S[H - 1][1] == '#') ? info = true : info = false;
  if (S[H - 1][0] == '#') (S[H - 2][0] == '#') ? info = true : info = false;
  if (S[0][W - 1] == '#') (S[1][W - 1] == '#') ? info = true : info = false;
  if (S[0][W - 1] == '#') (S[0][W - 2] == '#') ? info = true : info = false;
  if (S[H - 1][W - 1] == '#')
    (S[H - 2][W - 1] == '#') ? info = true : info = false;
  if (S[H - 1][W - 1] == '#')
    (S[H - 1][W - 2] == '#') ? info = true : info = false;
  if (info)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
}
