#include <bits/stdc++.h>
using namespace std;
int h, w;
int dx[] = {1, 0, -1, 0};
int dy[] = {0, 1, 0, -1};
vector<string> s;
bool seen[100][100];
void dfs(int x, int y) {
  for (int i = 0; i < 4; i++) {
    int nx = x + dx[i];
    int ny = y + dy[i];
    if (nx < 0 || w <= nx || ny < 0 || h <= ny) continue;
    if (s[nx][ny] != '#') continue;
    if (seen[nx][ny]) continue;
    if (s[x][y] == '#' && s[nx][ny] == '#') {
      seen[x][y] = true;
      seen[nx][ny] = true;
      dfs(nx, ny);
    }
  }
}
int main() {
  cin >> h >> w;
  s.resize(h);
  for (int i = 0; i < h; i++) {
    cin >> s[i];
  }
  int cnt = 0;
  for (int i = 0; i < h; i++) {
    for (int j = 0; j < w; j++) {
      if (s[i][j] == '#') cnt++;
    }
  }
  memset(seen, 0, sizeof(seen));
  for (int i = 0; i < h; i++) {
    for (int j = 0; j < w; j++) {
      if (s[j][i] == '#') dfs(j, i);
    }
  }
  int ans = 0;
  for (int i = 0; i < h; i++) {
    for (int j = 0; j < w; j++) {
      if (seen[i][j]) ans++;
    }
  }
  if (cnt == ans)
    cout << "Yes" << endl;
  else
    cout << "No" << endl;
}
