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#include <bits/stdc++.h>
using namespace std;
bool primecheck(long long int a) {
  bool check = true;
  if (a == 1) return (false);
  for (long long int i = 2; i <= sqrt(a); i++) {
    if (a % i == 0) {
      check = false;
      break;
    }
  }
  return (check);
}
vector<long long int> primeFactors(long long int n) {
  vector<long long int> sol;
  bool once = false;
  while (n % 2 == 0) {
    if (!once) {
      sol.push_back(2);
      once = true;
    }
    n = n / 2;
  }
  for (int i = 3; i <= sqrt(n); i = i + 2) {
    bool once = false;
    while (n % i == 0) {
      if (!once) {
        sol.push_back(i);
        once = true;
      }
      n = n / i;
    }
  }
  if (n > 2) {
    sol.push_back(n);
  }
  return (sol);
}
vector<long long int> printDivisors(long long int n) {
  vector<long long int> sol;
  for (long long int i = 1; i <= sqrt(n); i++) {
    if (n % i == 0) {
      if (n / i == i) {
        sol.push_back(i);
      } else {
        sol.push_back(i);
        sol.push_back(n / i);
      }
    }
  }
  return (sol);
}
long long int digits(long long int a) { return (floor(log10(a)) + 1); }
long long int bits(long long int n) { return __builtin_popcount(n); }
long long binpow(long long a, long long b, long long m) {
  a %= m;
  long long res = 1;
  while (b > 0) {
    if (b & 1) res = res * a % m;
    a = a * a % m;
    b >>= 1;
  }
  return res;
}
long long int modInverse(long long int a, long long int m) {
  long long int m0 = m;
  long long int y = 0, x = 1;
  if (m == 1) return 0;
  while (a > 1) {
    long long int q = a / m;
    long long int t = m;
    m = a % m, a = t;
    t = y;
    y = x - q * y;
    x = t;
  }
  if (x < 0) x += m0;
  return x;
}
int gcd(int a, int b) {
  if (a == 0) return b;
  if (b == 0) return a;
  if (a == b) return a;
  if (a > b) return gcd(a - b, b);
  return gcd(a, b - a);
}
long long int lcm(long long int a, long long int b) {
  return (a * b) / gcd(a, b);
}
void addEdge(vector<long long int> adj[], long long int u, long long int v) {
  adj[u].push_back(v);
  adj[v].push_back(u);
}
vector<long long int> path;
void dfs(long long int u, vector<long long int> adj[], vector<bool> &visited,
         long long int parent = -1) {
  visited[u] = true;
  path[u] = parent;
  for (long long int i = 0; i < adj[u].size(); i++) {
    if (visited[adj[u][i]] == false) {
      dfs(adj[u][i], adj, visited, u);
    }
  }
}
char graph[50][50];
bool visited[50][50];
deque<pair<long long int, long long int> > que;
vector<long long int> row;
vector<long long int> cols;
void move(long long int a, long long int b) {
  long long int i, j, k, l;
  while (!que.empty()) {
    pair<long long int, long long int> top = que.front();
    que.pop_front();
    row[top.first]++;
    cols[top.second]++;
    for (i = 0; i < a; i++) {
      if (graph[i][top.second] == '#' && visited[i][top.second] == false) {
        visited[i][top.second] = true;
        que.push_back(make_pair(i, top.second));
      }
    }
    for (i = 0; i < b; i++) {
      if (graph[top.first][i] == '#' && visited[top.first][i] == false) {
        visited[top.first][i] = true;
        que.push_back(make_pair(top.first, i));
      }
    }
  }
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long int a, b, c, i, j, k, l, m, n, t, p;
  cin >> a >> b;
  for (i = 0; i < a; i++) {
    for (j = 0; j < b; j++) {
      cin >> graph[i][j];
      visited[i][j] = false;
    }
  }
  vector<long long int> row_fin(a, 0);
  vector<long long int> cols_fin(b, 0);
  bool possible = true;
  for (i = 0; i < a; i++) {
    for (j = 0; j < b; j++) {
      if (graph[i][j] == '#') {
        row.clear();
        que.clear();
        cols.clear();
        for (k = 0; k < 50; k++) {
          row.push_back(0);
          cols.push_back(0);
        }
        que.push_back(make_pair(i, j));
        move(a, b);
        for (m = 0; m < a; m++) {
          for (n = 0; n < b; n++) {
            if (row[m] && cols[n]) {
              if (graph[m][n] == '.')
                possible = false;
              else
                graph[m][n] = '.';
            }
          }
        }
        for (i = 0; i < a; i++) {
          if (row[i]) {
            row_fin[i]++;
            if (row_fin[i] > 1) possible = false;
          }
        }
        for (i = 0; i < b; i++) {
          if (cols[i]) {
            cols_fin[i]++;
            if (cols_fin[i] > 1) possible = false;
          }
        }
      }
    }
  }
  if (possible)
    cout << "Yes"
         << "\n";
  else {
    cout << "No"
         << "\n";
  }
}
