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#include <bits/stdc++.h>
using namespace std;
const int INF = (int)(1e9 + 1e5);
const long long LINF = (long long)(4e18);
const double EPS = 1e-6;
const int MOD = (int)1e9 + 7;
const int MAXN = 50;
int n, m;
int was[2][MAXN];
char table[MAXN][MAXN];
char my_table[MAXN][MAXN];
vector<int> cur[2];
int en[2], bg[2];
void solve() {
  cin >> n >> m;
  for (int i = 0; i < n; ++i) {
    for (int j = 0; j < m; ++j) {
      cin >> table[i][j];
      my_table[i][j] = '.';
    }
  }
  for (int i = 0; i < n; ++i) {
    if (was[0][i]) {
      continue;
    }
    was[0][i] = 1;
    en[0]++;
    cur[0].push_back(i);
    while (bg[0] < en[0] || bg[1] < en[1]) {
      while (bg[0] < en[0]) {
        int x = cur[0][bg[0]];
        bg[0]++;
        for (int y = 0; y < m; ++y) {
          if (table[x][y] == '#') {
            if (!was[1][y]) {
              was[1][y] = 1;
              en[1]++;
              cur[1].push_back(y);
            }
          }
        }
      }
      while (bg[1] < en[1]) {
        int y = cur[1][bg[1]];
        bg[1]++;
        for (int x = 0; x < m; ++x) {
          if (table[x][y] == '#') {
            if (!was[0][x]) {
              was[0][x] = 1;
              en[0]++;
              cur[0].push_back(x);
            }
          }
        }
      }
    }
    for (int x = 0; x < (int)cur[0].size(); ++x) {
      for (int y = 0; y < (int)cur[1].size(); ++y) {
        my_table[cur[0][x]][cur[1][y]] = '#';
      }
    }
    en[0] = 0;
    en[1] = 0;
    bg[0] = 0;
    bg[1] = 0;
    cur[0].clear();
    cur[1].clear();
  }
  int flag = 0;
  for (int i = 0; i < n; ++i) {
    for (int j = 0; j < m; ++j) {
      if (table[i][j] != my_table[i][j]) {
        flag = 1;
      }
    }
  }
  if (flag) {
    cout << "No";
  } else {
    cout << "Yes";
  }
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  int t = 1;
  for (int i = 0; i < t; ++i) {
    solve();
  }
  return 0;
}
