#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m, flag = 0;
  cin >> n >> m;
  vector<int> adj[m + 1];
  char grid[n + 1][m + 1];
  bool vis[m + 1];
  char black = '#';
  for (int i = 1; i <= n; i++)
    for (int j = 1; j <= m; j++) cin >> grid[i][j];
  for (int i = 1; i <= m; i++) vis[i] = false;
  for (int i = 1; i <= n; i++) {
    int c = 0, b = 0, r;
    for (int j = 1; j <= m; j++) {
      if (grid[i][j] == black) b++;
    }
    for (int j = 1; j <= m; j++) {
      if (grid[i][j] == black && c == 0) {
        if (vis[j]) {
          if (b != adj[j].size()) {
            flag = 1;
            break;
          }
          for (int k = 0; k < adj[j].size(); k++) {
            if (grid[i][adj[j][k]] != black) {
              flag = 1;
              break;
            }
          }
          break;
        } else {
          adj[j].push_back(j);
          r = j;
          vis[j] = true;
          c++;
        }
      } else if (grid[i][j] == black) {
        if (vis[j]) {
          flag = 1;
          break;
        } else {
          adj[r].push_back(j);
          vis[j] = true;
        }
      }
      if (flag == 1) break;
    }
    if (flag == 1) break;
  }
  if (flag == 1)
    cout << "No";
  else
    cout << "Yes";
  return 0;
}
