#include <bits/stdc++.h>
const double Pi = 3.14159265;
const double e = 2.71828182;
const int N = 1e2 + 5;
const unsigned long long base = 163;
const long long INF = 0x3f3f3f3f;
using namespace std;
string str[N];
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n, m;
  cin >> n >> m;
  for (int i = 0; i < n; i++) {
    cin >> str[i];
  }
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < m; j++) {
      if (str[i][j] == '#') {
        for (int k = i + 1; k < n; k++) {
          if (str[k][j] == '#') {
            for (int l = j - 1; l >= 0; l--) {
              if (str[k][l] != str[i][l]) {
                return cout << "No\n", 0;
              }
            }
            for (int l = j + 1; l < m; l++) {
              if (str[k][l] != str[i][l]) {
                return cout << "No\n", 0;
              }
            }
          }
        }
      }
    }
  }
  cout << "Yes\n";
  return 0;
}
