#include <bits/stdc++.h>
using namespace std;
const long long MOD = 1000000007;
const long long INF = 1000000007ll * 1000000007ll;
const long long N = 300002;
const long long logN = 20;
const long double PI = acos(-1);
const long long HashPrime = 31;
inline void No() { puts("No"); }
inline void Yes() { puts("Yes"); }
string s[52];
string c[52];
void solve() {
  int n, m;
  cin >> n >> m;
  for (int i = 0; i < n; ++i) {
    cin >> s[i];
    for (int j = 0; j < m; ++j) {
      c[j] += s[i][j];
    }
  }
  for (int i = 0; i < n; ++i) {
    string str = "";
    for (int j = 0; j < m; ++j) {
      if (s[i][j] == '#') {
        if (str.empty()) {
          str = c[j];
        }
        if (str != c[j]) {
          No();
          return;
        }
      }
    }
    for (int j = 0; j < str.size(); ++j) {
      if (str[j] == '#') {
        if (s[j] != s[i]) {
          No();
          return;
        }
      }
    }
  }
  Yes();
}
int main() {
  long long t = 1;
  while (t--) {
    solve();
  }
  return 0;
}
