#include <bits/stdc++.h>
using namespace std;
const int MAXN = 51;
char a[MAXN][MAXN];
int id[MAXN];
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int n, m;
  cin >> n >> m;
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < m; j++) {
      cin >> a[i][j];
    }
  }
  int cur = 1;
  for (int i = 0; i < n; i++) {
    vector<int> t;
    for (int j = 0; j < m; j++) {
      if (a[i][j] == '#') {
        t.push_back(id[j]);
      }
    }
    if (t.size() > 0) {
      int elem = t[0];
      for (int u : t) {
        if (u != elem) {
          cout << "No" << endl;
          return 0;
        }
      }
      if (elem == 0) {
        for (int j = 0; j < m; j++) {
          if (a[i][j] == '#') {
            id[j] = cur;
          }
        }
        cur += 1;
      } else {
        for (int j = 0; j < m; j++) {
          if ((id[j] == elem) and (a[i][j] != '#')) {
            cout << "No" << endl;
            return 0;
          }
        }
      }
    }
  }
  cout << "Yes" << endl;
  return 0;
}
