#include <bits/stdc++.h>
using namespace std;
int mod = 1000000007;
string a[100];
int col[100];
int main() {
  int n, m;
  cin >> n >> m;
  for (int i = 0; i < (int)(n); ++i) {
    cin >> a[i];
  }
  for (int j = 0; j < (int)(m); ++j) {
    col[j] = -1;
  }
  int cur = 0;
  for (int i = 0; i < (int)(n); ++i) {
    set<int> s;
    for (int j = 0; j < (int)(m); ++j) {
      if (a[i][j] == '#') {
        s.insert(col[j]);
      }
    }
    if (s.size() == 0) {
      continue;
    }
    if (s.size() > 1) {
      cout << "No\n";
      return 0;
    }
    int c = *s.begin();
    if (c == -1) {
      c = cur++;
    }
    for (int j = 0; j < (int)(m); ++j) {
      if (a[i][j] == '#') {
        col[j] = c;
      }
      if (a[i][j] == '.' && col[j] == c) {
        cout << "No\n";
        return 0;
      }
    }
  }
  cout << "Yes\n";
  return 0;
}
