#include <bits/stdc++.h>
using namespace std;
int n, m;
char mat[100][100];
char c;
vector<int> us;
int main() {
  cin >> n >> m;
  for (int i = 0; i < n; i++) cin >> mat[i];
  for (int i = 0; i < n; i++) {
    us.clear();
    for (int j = 0; j < m; j++) {
      if (mat[i][j] == '#') us.push_back(j);
    }
    if (us.size() > 0) {
      for (int j = 0; j < n; j++) {
        c = mat[j][us[0]];
        for (int k = 1; k < (int)us.size(); k++) {
          if (mat[j][us[k]] != c) {
            cout << "No";
            return 0;
          }
        }
      }
    }
  }
  for (int i = 0; i < m; i++) {
    us.clear();
    for (int j = 0; j < n; j++) {
      if (mat[j][i] == '#') us.push_back(j);
    }
    if (us.size() > 0) {
      for (int j = 0; j < m; j++) {
        c = mat[us[0]][j];
        for (int k = 1; k < (int)us.size(); k++) {
          if (mat[us[k]][j] != c) {
            cout << "No";
            return 0;
          }
        }
      }
    }
  }
  cout << "Yes";
  return 0;
}
