#include <bits/stdc++.h>
void Init() {
  std::cin.tie(0);
  std::ios::sync_with_stdio(false);
  struct Init_caller {
    Init_caller() { Init(); }
  } caller;
}
using namespace std;
using LL = long long;
using st = string;
using vi = vector<LL>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vd = vector<double>;
using vvd = vector<vd>;
using vvvd = vector<vvd>;
using vc = vector<char>;
using vvc = vector<vc>;
using vs = vector<st>;
using vb = vector<bool>;
using vvb = vector<vb>;
using vvvb = vector<vvb>;
using qi = queue<LL>;
using qc = queue<char>;
using qs = queue<st>;
using si = stack<LL>;
using sc = stack<char>;
using ss = stack<st>;
using pi = pair<LL, LL>;
using ppi = pair<pi, LL>;
using mll = map<LL, LL>;
using mcl = map<char, LL>;
using vpi = vector<pi>;
using vppi = vector<ppi>;
using qpi = queue<pi>;
LL cross_x[] = {-1, 0, 0, 1};
LL cross_y[] = {0, 1, -1, 0};
struct edge {
  LL f, t, c;
};
void y_n(bool p) {
  p ? cout << "Yes"
           << "\n"
    : cout << "No"
           << "\n";
}
void Y_N(bool p) {
  p ? cout << "YES"
           << "\n"
    : cout << "NO"
           << "\n";
}
LL vmax(vi v, LL n) {
  LL MAX = 0;
  for (LL i = 0; i < n; i++) {
    MAX = max(MAX, v[i]);
  }
  return MAX;
}
LL vmin(vi v, LL n) {
  LL MIN = 1LL << 60;
  for (LL i = 0; i < n; i++) {
    MIN = min(MIN, v[i]);
  }
  return MIN;
}
LL gcd(LL a, LL b) {
  if (b == 0) {
    swap(a, b);
  }
  LL r;
  while ((r = a % b) != 0) {
    a = b;
    b = r;
  }
  return b;
}
LL lcm(LL a, LL b) { return (a / gcd(a, b) * b); }
bool is_prime(LL n) {
  for (LL i = 2; i * i <= n; i++) {
    if (n % i == 0) {
      return false;
    }
  }
  return true;
}
void dec_prime(LL n) {
  LL a = 2;
  while (a * a <= n) {
    if (n % a == 0) {
      cout << a << "\n";
      n /= a;
    } else {
      a++;
    }
  }
  cout << n << "\n";
}
void sieve_prime(LL n) {
  vb s(n + 1, true);
  for (LL i = 2; i < n + 1; i++) {
    for (LL j = 2; i * j <= n; j++) {
      s[i * j] = false;
    }
  }
  cout << "2から" << n << "までの素数"
       << "\n";
  for (LL i = 2; i < n + 1; i++) {
    if (s[i]) {
      cout << i << " ";
    }
  }
}
LL factorial(LL n) {
  LL a = 1, ret = 1;
  while (a < n) {
    a++;
    ret *= a;
  }
  return ret;
}
vi par;
LL root(LL x) {
  if (par[x] == x) {
    return x;
  } else {
    return par[x] = root(par[x]);
  }
}
void unite(LL x, LL y) {
  if (root(x) == root(y)) {
    return;
  } else {
    par[root(x)] = root(y);
    return;
  }
}
bool same(LL x, LL y) { return root(x) == root(y); }
LL dx[] = {-1, -1, 1, 1};
LL dy[] = {1, -1, 1, -1};
signed main() {
  LL h, w;
  cin >> h >> w;
  vs s(h);
  for (LL i = 0; i < h; i++) {
    cin >> s[i];
  }
  bool f = false;
  for (LL x = 0; x < w; x++) {
    for (LL y = 0; y < h; y++) {
      if (s[x][y] == '#') {
        for (LL i = 0; i < 4; i++) {
          LL nx = x + cross_x[i];
          LL ny = y + cross_y[i];
          if (nx < 0 || w <= nx || ny < 0 || h <= ny) {
            continue;
          }
          if (s[nx][ny] == '#') {
            f = true;
          }
        }
      }
    }
  }
  y_n(f);
  return 0;
}
