#include <bits/stdc++.h>
const long long INF = LLONG_MAX / 10;
using namespace std;
const long long dx[9] = {-1, 0, 0, 1, -1, -1, 1, 1, 0};
const long long dy[9] = {0, -1, 1, 0, -1, 1, -1, 1, 0};
long long n, m;
char grid[55][55];
bool rused[55], cused[55];
bool trused[55], tcused[55];
bool checked[55][55];
void dfs(long long r, long long c) {
  trused[r] = tcused[c] = true;
  for (long long i = 0; i < (n); i++) {
    if (i == r) continue;
    if (trused[i]) continue;
    if (grid[i][c] == '#') dfs(i, c);
  }
  for (long long i = 0; i < (m); i++) {
    if (i == c) continue;
    if (tcused[i]) continue;
    if (grid[r][i] == '#') dfs(r, i);
  }
}
signed main() {
  cin >> n >> m;
  for (long long i = 0; i < (n); i++)
    for (long long j = 0; j < (m); j++) cin >> grid[i][j];
  for (long long i = 0; i < (n); i++) {
    for (long long j = 0; j < (m); j++) {
      if (grid[i][j] == '#') {
        if (rused[i] || cused[j]) {
          cout << "No" << endl;
          return 0;
        }
        dfs(i, j);
        for (long long ii = 0; ii < (n); ii++)
          for (long long jj = 0; jj < (m); jj++) {
            if (trused[ii] && !tcused[jj] && grid[ii][jj] == '#') {
              cout << "No" << endl;
              return 0;
            }
            if (!trused[ii] && tcused[jj] && grid[ii][jj] == '#') {
              cout << "No" << endl;
              return 0;
            }
            if (trused[ii] && tcused[jj] && grid[ii][jj] == '.') {
              cout << "No" << endl;
              return 0;
            }
          }
        for (long long ii = 0; ii < (n); ii++)
          for (long long jj = 0; jj < (m); jj++)
            if (trused[ii] && tcused[jj]) {
              grid[ii][jj] = '.';
            }
        for (long long ii = 0; ii < (n); ii++) {
          rused[ii] |= trused[ii];
        }
        for (long long jj = 0; jj < (m); jj++) {
          cused[jj] |= tcused[jj];
        }
        for (long long ii = 0; ii < (n); ii++) trused[ii] = false;
        for (long long jj = 0; jj < (m); jj++) tcused[jj] = false;
        break;
      }
    }
  }
  cout << "Yes" << endl;
}
