#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m;
  cin >> n >> m;
  char arr[n][m];
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < m; j++) {
      cin >> arr[i][j];
    }
  }
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < m; j++) {
      if (arr[i][j] != '#') continue;
      for (int x = 0; x < n; x++) {
        for (int y = 0; y < m; y++) {
          if (arr[x][y] != '#' || i == x || j == y) continue;
          if (arr[i][y] == '#' && arr[x][j] != '#' ||
              arr[i][y] != '#' && arr[x][j] == '#') {
            cout << "No";
            return 0;
          }
        }
      }
    }
  }
  cout << "Yes";
  return 0;
}
