#include <bits/stdc++.h>
using namespace std;
int main() {
  int N, M;
  cin >> N >> M;
  string s[N];
  for (int lol = 0; lol < N; lol++) {
    cin >> s[lol];
  }
  int yes = 0;
  for (int lol = 0; lol < N; lol++) {
    for (int i = 0; i < M; i++) {
      if (s[lol][i] == '#') {
        for (int j = 0; j < N; j++) {
          if (s[j][i] == '#') {
            if (j != lol) {
              for (int j2 = 0; j2 < M; j2++) {
                if (s[lol][j2] != s[j][j2]) {
                  yes = 1;
                }
              }
            }
          }
        }
        for (int k = 0; k < M; k++) {
          if (s[lol][k] == '#') {
            if (k != i) {
              for (int j2 = 0; j2 < N; j2++) {
                if (s[j2][k] != s[j2][i]) {
                  yes = 1;
                }
              }
            }
          }
        }
      }
    }
  }
  if (yes) {
    cout << "No";
  } else {
    cout << "Yes";
  }
  return 0;
}
