#include <bits/stdc++.h>
using namespace std;
int main() {
  int H, W;
  std::cin >> H >> W;
  char s[H][W];
  for (int i = 0; i < H; i++) {
    for (int j = 0; j < W; j++) {
      std::cin >> s[i][j];
    }
  }
  bool flag = true;
  int check[51][51] = {0};
  for (int i = 0; i < H; i++) {
    for (int j = 0; j < W; j++) {
      if (s[i][j] == '#') {
        if (i == H - 1 && j == W - 1 && check[i][j] == 0) {
          flag = false;
        } else {
          if (i == H - 1) {
            if (s[i][j + 1] == '.' && check[i][j] == 0) {
              flag = false;
            } else if (s[i][j + 1] == '#')
              check[i][j + 1] = 1;
          } else if (j == W - 1) {
            if (s[i + 1][j] == '.' && check[i][j] == 0) {
              flag = false;
            } else if (s[i + 1][j] == '#')
              check[i + 1][j] = 1;
          } else {
            if (s[i + 1][j] == '#' || s[i][j + 1] == '#') {
              if (s[i][j + 1] == '#') check[i][j + 1] = 1;
              if (s[i + 1][j] == '#') check[i + 1][j] = 1;
            } else {
              if (check[i][j] = 0) {
                flag = false;
              }
            }
          }
        }
      }
    }
  }
  if (flag)
    std::cout << "Yes" << std::endl;
  else
    std::cout << "No" << std::endl;
  return 0;
}
