#include <bits/stdc++.h>
using namespace std;
int n, m;
char fi[55][55];
bool vis[55];
bool tmp[55];
bool valid = 1;
int com(int r) {
  int ret = 3;
  for (int i = 1; i <= m; i++) {
    if (ret == 2) return ret;
    if (tmp[i] && fi[r][i] == '#') {
      if (ret == 3)
        ret = 1;
      else if (ret == 0)
        return 2;
    } else if (tmp[i] && fi[r][i] != '#') {
      if (ret == 3)
        ret = 0;
      else if (ret == 1)
        return 2;
    } else if (!tmp[i] && fi[r][i] == '#') {
      if (ret == 3)
        ret = 0;
      else if (ret == 1)
        return 2;
    }
  }
  return ret;
}
void cek(int r) {
  for (int i = r + 1; i <= n; i++) {
    int coba = com(i);
    if (coba == 0 || coba == 3)
      continue;
    else if (coba == 1) {
      vis[i] = 1;
    } else {
      valid = 0;
      return;
    }
  }
  return;
}
int main() {
  memset(vis, 0, sizeof(vis));
  scanf("%d%d", &n, &m);
  for (int i = 1; i <= n; i++) {
    getchar();
    for (int j = 1; j <= m; j++) {
      scanf("%c", &fi[i][j]);
    }
  }
  for (int i = 1; i <= n; i++) {
    if (vis[i]) continue;
    vis[i] = 1;
    memset(tmp, 0, sizeof(tmp));
    for (int j = 1; j <= m; j++) {
      if (fi[i][j] == '#') {
        tmp[j] = 1;
      }
    }
    cek(i);
    if (!valid) break;
  }
  if (valid)
    printf("Yes\n");
  else
    printf("No\n");
  return 0;
}
