#include <bits/stdc++.h>
using namespace std;
int flag[50];
char **CreatArray(int row, int col) {
  char **arr = new char *[row];
  for (int i = 0; i < row; i++) {
    arr[i] = new char[col];
  }
  return arr;
}
void DeleteArray(int row, char **arr) {
  for (int i = 0; i < row; i++) {
    delete[] arr[i];
  }
}
int CheckCol(int row1, int col1, int row2, int col, char **arr) {
  for (int i = 0; i < col; i++) {
    if (i == col1) continue;
    if (arr[row1][i] == '#')
      if (arr[row2][i] != '#') {
        return 1;
        ;
      }
  }
  for (int j = 0; j < col; j++) {
    if (j == col1) continue;
    if (arr[row2][j] == '#')
      if (arr[row1][j] != '#') {
        return 1;
      }
  }
  return 0;
}
int main() {
  int row, col;
  cin >> row >> col;
  char **arr = CreatArray(row, col);
  for (int i = 0; i < row; i++) {
    flag[i] = 0;
    for (int j = 0; j < col; j++) {
      cin >> arr[i][j];
    }
  }
  for (int i = 0; i < row; i++) {
    for (int j = 0; j < col; j++) {
      if (arr[i][j] == '#') {
        if (flag[i] == 1) continue;
        for (int k = i + 1; k < row; k++) {
          if (arr[k][j] == '#') {
            flag[k] = 1;
            if (CheckCol(i, j, k, col, arr) == 1) {
              cout << "No" << endl;
              return 0;
            }
          } else
            continue;
        }
      } else
        continue;
    }
  }
  cout << "Yes" << endl;
  DeleteArray(row, arr);
  return 0;
}
