#include <bits/stdc++.h>
using namespace std;
const int INF = 1000000;
vector<int> dx = {1, 1, -1, -1};
vector<int> dy = {1, -1, 1, -1};
int main(){
  int H, W;
  cin >> H >> W;
  vector<vector<char>> S(H, vector<char>(W));
  for (int i = 0; i < H; i++){
    for (int j = 0; j < W; j++){
      cin >> S[i][j];
    }
  }
  vector<vector<vector<int>>> C(4, vector<vector<int>>(H, vector<int>(W, -1)));
  for (int i = 0; i < 2; i++){
    for (int j = 0; j < H; j++){
      for (int k = 0; k < W; k++){
        if (S[j][k] == '#'){
          C[i][j][k] = 0;
          if (j > 0 && 0 <= k - dy[i] && k - dy[i] < W){
            C[i][j][k] = C[i][j - 1][k - dy[i]] + 1;
          }
        }
      }
    }
  }
  for (int i = 2; i < 4; i++){
    for (int j = H - 1; j >= 0; j--){
      for (int k = 0; k < W; k++){
        if (S[j][k] == '#'){
          C[i][j][k] = 0;
          if (j <= H - 2 && 0 <= k - dy[i] && k - dy[i] < W){
            C[i][j][k] = C[i][j + 1][k - dy[i]] + 1;
          }
        }
      }
    }
  }
  vector<vector<int>> D(H, vector<int>(W, INF));
  for (int i = 0; i < H; i++){
    for (int j = 0; j < W; j++){
      for (int k = 0; k < 4; k++){
        D[i][j] = min(D[i][j], C[k][i][j]);
      }
      if (D[i][j] == 0){
        D[i][j] = -1;
      }
    }
  }
  vector<vector<vector<int>>> D2(4, D);
  for (int i = 0; i < 2; i++){
    for (int j = H - 2; j >= 0; j--){
      for (int k = 0; k < W; k++){
        if (0 <= k + dy[i] && k + dy[i] < W){
          D2[i][j][k] = max(D2[i][j][k], D2[i][j + 1][k + dy[i]] - 1);
        }
      }
    }
  }
  for (int i = 2; i < 4; i++){
    for (int j = 1; j < H; j++){
      for (int k = 0; k < W; k++){
        if (0 <= k + dy[i] && k + dy[i] < W){
          D2[i][j][k] = max(D2[i][j][k], D2[i][j - 1][k + dy[i]] - 1);
        }
      }
    }
  }
  bool ok = true;
  for (int i = 0; i < H; i++){
    for (int j = 0; j < W; j++){
      if (S[i][j] == '#'){
        bool ok2 = false;
        for (int k = 0; k < 4; k++){
          if (D2[k][i][j] >= 0){
            ok2 = true;
          }
        }
        if (!ok2){
          ok = false;
        }
      }
    }
  }
  if (ok){
    cout << "Yes" << endl;
  } else {
    cout << "No" << endl;
  }
}