#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("sse4")
using namespace std;
long long row[100];
set<long long> r[100];
int32_t main() {
  long long n, m;
  long long f = 0;
  cin >> n >> m;
  long long i, j;
  char a[n + 5][m + 5];
  for (i = 1; i <= n; i++) {
    string s;
    cin >> s;
    for (j = 1; j <= m; j++) a[i][j] = s[j - 1];
  }
  for (j = 1; j <= m; j++) {
    vector<long long> v;
    for (i = 1; i <= n; i++)
      if (a[i][j] == '#') v.push_back(i);
    if (v.size() > 0) {
      if (row[v[0]]) {
        long long sz = r[v[0]].size();
        if (sz != v.size() - 1) {
          f = 1;
          break;
        }
        auto it = r[v[0]].begin();
        for (i = 1; i < v.size(); i++) {
          if (v[i] != *it) {
            f = 1;
            break;
          }
          it++;
        }
      } else {
        for (i = 0; i < v.size(); i++)
          if (row[v[i]]) {
            f = 1;
            break;
          } else {
            row[v[i]] = 1;
            if (i > 0) {
              r[v[0]].insert(v[i]);
              r[v[i]].insert(v[0]);
            }
          }
      }
    }
    if (f) break;
  }
  if (j <= m)
    cout << "No\n";
  else
    cout << "Yes\n";
  return 0;
}
