#pragma GCC optimize("O2")
#include <algorithm>
#include <array>
#include <bit>
#include <bitset>
#include <cassert>
#include <cctype>
#include <cfenv>
#include <cfloat>
#include <chrono>
#include <cinttypes>
#include <climits>
#include <cmath>
#include <compare>
#include <complex>
#include <concepts>
#include <cstdarg>
#include <cstddef>
#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <deque>
#include <fstream>
#include <functional>
#include <initializer_list>
#include <iomanip>
#include <ios>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <map>
#include <memory>
#include <new>
#include <numbers>
#include <numeric>
#include <ostream>
#include <queue>
#include <random>
#include <ranges>
#include <set>
#include <span>
#include <sstream>
#include <stack>
#include <streambuf>
#include <string>
#include <tuple>
#include <type_traits>
#include <variant>

#define int ll
#define INT128_MAX (__int128)(((unsigned __int128) 1 << ((sizeof(__int128) * __CHAR_BIT__) - 1)) - 1)
#define INT128_MIN (-INT128_MAX - 1)

#define clock chrono::steady_clock::now().time_since_epoch().count()

#ifdef DEBUG
#define dbg(x) cout << (#x) << " = " << x << '\n'
#else
#define dbg(x)
#endif

namespace R = std::ranges;
namespace V = std::views;

using namespace std;

using ll = long long;
using ull = unsigned long long;
using ldb = long double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
//#define double ldb

template<class T>
ostream& operator<<(ostream& os, const pair<T, T> pr) {
  return os << pr.first << ' ' << pr.second;
}
template<class T, size_t N>
ostream& operator<<(ostream& os, const array<T, N> &arr) {
  for(const T &X : arr)
    os << X << ' ';
  return os;
}
template<class T>
ostream& operator<<(ostream& os, const vector<T> &vec) {
  for(const T &X : vec)
    os << X << ' ';
  return os;
}
template<class T>
ostream& operator<<(ostream& os, const set<T> &s) {
  for(const T &x : s)
    os << x << ' ';
  return os;
}


signed main() {
  ios::sync_with_stdio(false), cin.tie(NULL);

  int h, w; cin >> h >> w;
  vector g(h + 2, string(w + 2, '.'));
  for(int i = 1; i <= h; i++) {
    string s; cin >> s;
    g[i] = '.' + s + '.';
  }

  vector dp(4, vector(h + 2, vector<int>(w + 2)));
  for(int i = 1; i <= h; i++) {
    for(int j = 1; j <= w; j++) {
      if (g[i][j] == '.') continue;
      dp[0][i][j] = dp[0][i - 1][j - 1] + 1;
      dp[1][i][j] = dp[1][i - 1][j + 1] + 1;
    }
  }
  for(int i = h; i >= 1; i--) {
    for(int j = 1; j <= w; j++) {
      if (g[i][j] == '.') continue;
      dp[2][i][j] = dp[2][i + 1][j - 1] + 1;
      dp[3][i][j] = dp[3][i + 1][j + 1] + 1;
    }
  }

  vector pre(2, vector(h + 2, vector<int>(w + 2)));
  for(int i = 1; i <= h; i++) {
    for(int j = 1; j <= w; j++) {
      if (g[i][j] == '.') continue;
      int d = min({dp[0][i][j], dp[1][i][j], dp[2][i][j], dp[3][i][j]});
      if (d <= 1) continue;
      pre[0][i - d + 1][j - d + 1]++, pre[0][i + d][j + d]--;
      pre[1][i - d + 1][j + d - 1]++, pre[1][i + d][j - d]--;
    }
  }

  for(int i = 1; i <= h; i++)
    for(int j = 1; j <= w; j++)
      pre[0][i][j] += pre[0][i - 1][j - 1], pre[1][i][j] += pre[1][i - 1][j + 1];

  bool ok = true;
  for(int i = 1; i <= h; i++)
    for(int j = 1; j <= w; j++)
      if (g[i][j] == '#')
        ok = ok and (pre[0][i][j] + pre[1][i][j] > 0);

  cout << (ok ? "Yes\n" : "No\n");

  return 0;
}