#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m;
  cin >> n >> m;
  char ar[n][m];
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < m; j++) {
      cin >> ar[i][j];
    }
  }
  int f = 1;
  int sc[m];
  for (int i = 0; i < m; i++) sc[i] = -1;
  for (int i = 0; i < n; i++) {
    int cont = -1;
    for (int j = 0; j < m; j++) {
      if (ar[i][j] == '#' && sc[j] != -1) {
        cont = sc[j];
      }
    }
    if (cont != -1) {
      for (int j = 0; j < m; j++) {
        if (ar[i][j] == '#' && sc[j] != cont) {
          f = 0;
          break;
        }
        if (sc[j] == cont && ar[i][j] != '#') {
          f = 0;
          break;
        }
      }
    } else {
      for (int j = 0; j < m; j++) {
        if (ar[i][j] == '#') {
          sc[j] = i;
        }
      }
    }
  }
  if (f) {
    cout << "Yes\n";
  } else {
    cout << "No\n";
  }
  return 0;
}
