#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long;
using i_i = pair<int, int>;
using ll_ll = pair<ll, ll>;
using d_ll = pair<double, ll>;
using ll_d = pair<ll, double>;
using d_d = pair<double, double>;
static constexpr ll LL_INF = 1LL << 60;
static constexpr int I_INF = 1 << 28;
static constexpr double PI =
    static_cast<double>(3.14159265358979323846264338327950288);
static constexpr double EPS = numeric_limits<double>::epsilon();
static constexpr const char* YES = "Yes";
static constexpr const char* NO = "No";
static map<type_index, const char* const> scanType = {{typeid(int), "%d"},
                                                      {typeid(ll), "%lld"},
                                                      {typeid(double), "%lf"},
                                                      {typeid(char), "%c"}};
template <class T>
static void scan(vector<T>& v);
[[maybe_unused]] static void scan(vector<string>& v, bool isWord = true);
template <class T>
static inline bool chmax(T& a, T b);
template <class T>
static inline bool chmin(T& a, T b);
template <class T>
static inline T gcd(T a, T b);
template <class T>
static inline T lcm(T a, T b);
template <class A, size_t N, class T>
static void Fill(A (&arr)[N], const T& val);
template <class T>
T mod(T a, T m);
int main(int argc, char* argv[]) {
  long long H;
  scanf("%lld", &H);
  long long W;
  scanf("%lld", &W);
  std::vector<std::string> s(W);
  for (int i = 0; i < W; i++) {
    std::cin >> s[i];
  }
  for (int i = (0); i < (H); i++)
    for (int j = (0); j < (W); j++) {
      bool adj = true;
      if (s[i][j] == '.') continue;
      if (i > 0) adj &= s[i - 1][j] == '.';
      if (i < H - 1) adj &= s[i + 1][j] == '.';
      if (j > 0) adj &= s[i][j - 1] == '.';
      if (j < W - 1) adj &= s[i][j + 1] == '.';
      if (adj) {
        ((cout) << (NO) << (endl));
        return 0;
      }
    }
  ((cout) << (YES) << (endl));
  return 0;
}
template <class T>
static void scan(vector<T>& v) {
  auto tFormat = scanType[typeid(T)];
  for (T& n : v) {
    scanf(tFormat, &n);
  }
}
static void scan(vector<string>& v, bool isWord) {
  if (isWord) {
    for (auto& n : v) {
      cin >> n;
    }
    return;
  }
  int i = 0, size = v.size();
  string s;
  getline(cin, s);
  if (s.size() != 0) {
    i++;
    v[0] = s;
  }
  for (; i < size; ++i) {
    getline(cin, v[i]);
  }
}
template <class T>
inline bool chmax(T& a, T b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T>
inline bool chmin(T& a, T b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T>
inline T gcd(T a, T b) {
  return __gcd(a, b);
}
template <class T>
inline T lcm(T a, T b) {
  return (a * b) / gcd(a, b);
}
template <class A, size_t N, class T>
void Fill(A (&arr)[N], const T& val) {
  std::fill((T*)arr, (T*)(arr + N), val);
}
template <class T>
T mod(T a, T m) {
  return (a % m + m) % m;
}
