#include <bits/stdc++.h>
int n, m;
char map[60][60] = {};
bool q[60] = {};
bool w[60] = {};
int main() {
  scanf("%d %d", &n, &m);
  for (int i = 1; i <= n; i++) {
    scanf("%s", map[i] + 1);
  }
  for (int i = 1; i <= n; i++) {
    bool chk[60] = {};
    bool temp[60] = {};
    for (int j = 1; j <= m; j++) {
      if (map[i][j] == '#') {
        for (int k = 1; k <= n; k++) {
          if (map[k][j] == '#') {
            if (q[k]) {
              printf("No\n");
              return 0;
            }
            chk[k] = true;
            q[k] = 1;
          }
        }
        for (int k = 1; k <= m; k++) {
          if (map[i][k] == '#') {
            if (w[k]) {
              printf("No\n");
              return 0;
            }
            w[k] = 1;
            temp[k] = true;
          }
        }
        for (int k = 1; k <= n; k++) {
          if (!chk[k]) continue;
          for (int l = 1; l <= m; l++) {
            if (!temp[l]) continue;
            if (map[k][l] != '#') {
              printf("No\n");
              return 0;
            } else
              map[k][l] = '.';
          }
        }
        map[i][j] = '.';
      }
    }
  }
  printf("Yes\n");
  return 0;
}
