#line 2 "/home/shogo314/cpp_include/ou-library/io.hpp"
/**
 * @file io.hpp
 * @brief 空白区切り出力、iostreamのオーバーロード
 */

#include <array>
#include <iostream>
#include <utility>
#include <tuple>
#include <vector>

namespace tuple_io {
    template <typename Tuple, size_t I, typename CharT, typename Traits>
    std::basic_istream<CharT, Traits>& read_tuple(std::basic_istream<CharT, Traits>& is, Tuple& t) {
        is >> std::get<I>(t);
        if constexpr (I + 1 < std::tuple_size_v<Tuple>) {
            return read_tuple<Tuple, I + 1>(is, t);
        }
        return is;
    }
    template <typename Tuple, size_t I, typename CharT, typename Traits>
    std::basic_ostream<CharT, Traits>& write_tuple(std::basic_ostream<CharT, Traits>& os, const Tuple& t) {
        os << std::get<I>(t);
        if constexpr (I + 1 < std::tuple_size_v<Tuple>) {
            os << CharT(' ');
            return write_tuple<Tuple, I + 1>(os, t);
        }
        return os;
    }
};

template <typename T1, typename T2, typename CharT, typename Traits>
std::basic_istream<CharT, Traits>& operator>>(std::basic_istream<CharT, Traits>& is, std::pair<T1, T2>& p) {
    is >> p.first >> p.second;
    return is;
}
template <typename... Types, typename CharT, typename Traits>
std::basic_istream<CharT, Traits>& operator>>(std::basic_istream<CharT, Traits>& is, std::tuple<Types...>& p) {
    return tuple_io::read_tuple<std::tuple<Types...>, 0>(is, p);
}
template <typename T, size_t N, typename CharT, typename Traits>
std::basic_istream<CharT, Traits>& operator>>(std::basic_istream<CharT, Traits>& is, std::array<T, N>& a) {
    for(auto& e : a) is >> e;
    return is;
}
template <typename T, typename CharT, typename Traits>
std::basic_istream<CharT, Traits>& operator>>(std::basic_istream<CharT, Traits>& is, std::vector<T>& v) {
    for(auto& e : v) is >> e;
    return is;
}

template <typename T1, typename T2, typename CharT, typename Traits>
std::basic_ostream<CharT, Traits>& operator<<(std::basic_ostream<CharT, Traits>& os, const std::pair<T1, T2>& p) {
    os << p.first << CharT(' ') << p.second;
    return os;
}
template <typename... Types, typename CharT, typename Traits>
std::basic_ostream<CharT, Traits>& operator<<(std::basic_ostream<CharT, Traits>& os, const std::tuple<Types...>& p) {
    return tuple_io::write_tuple<std::tuple<Types...>, 0>(os, p);
}
template <typename T, size_t N, typename CharT, typename Traits>
std::basic_ostream<CharT, Traits>& operator<<(std::basic_ostream<CharT, Traits>& os, const std::array<T, N>& a) {
    for(size_t i = 0; i < N; ++i) {
        if(i) os << CharT(' ');
        os << a[i];
    }
    return os;
}
template <typename T, typename CharT, typename Traits>
std::basic_ostream<CharT, Traits>& operator<<(std::basic_ostream<CharT, Traits>& os, const std::vector<T>& v) {
    for(size_t i = 0; i < v.size(); ++i) {
        if(i) os << CharT(' ');
        os << v[i];
    }
    return os;
}

/**
 * @brief 空行出力
 */
void print() { std::cout << '\n'; }
/**
 * @brief 出力して改行
 * 
 * @tparam T 型
 * @param x 出力する値
 */
template <typename T>
void print(const T& x) { std::cout << x << '\n'; }
/**
 * @brief 空白区切りで出力して改行
 * 
 * @tparam T 1つ目の要素の型
 * @tparam Tail 2つ目以降の要素の型
 * @param x 1つ目の要素
 * @param tail 2つ目以降の要素
 */
template <typename T, typename... Tail>
void print(const T& x, const Tail&... tail) {
    std::cout << x << ' ';
    print(tail...);
}
#line 1 "/home/shogo314/cpp_include/sh-library/base.hpp"
#include <bits/stdc++.h>

#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")

using namespace std;
using ll = long long;
using ull = unsigned long long;
using str = string;
using pl = pair<ll, ll>;
template <typename T>
using ml = map<ll, T>;
using mll = map<ll, ll>;
using sl = set<ll>;
using ld = long double;
using pd = pair<ld, ld>;
template <typename T>
using vec = vector<T>;
template <typename T>
using vv = vector<vector<T>>;
template <typename T>
using vvv = vector<vector<vector<T>>>;
template <typename T1, typename T2>
using vp = vector<pair<T1, T2>>;
using vl = vec<ll>;
using vvl = vv<ll>;
using vvvl = vvv<ll>;
using vs = vec<str>;
using vc = vec<char>;
using vi = vec<int>;
using vb = vec<bool>;
using vpl = vec<pl>;
using spl = set<pl>;
using vd = vec<ld>;
using vpd = vec<pd>;
template <typename T, int N>
using ary = array<T, N>;
template <int N>
using al = array<ll, N>;
template <int N1, int N2>
using aal = array<array<ll, N2>, N1>;
template <int N>
using val = vec<al<N>>;

#define all(obj) (obj).begin(), (obj).end()

#define reps(i, a, n) for (ll i = (a); i < ll(n); i++)
#define rep(i, n) reps(i, 0, (n))
#define rrep(i, n) reps(i, 1, (n) + 1)
#define repds(i, a, n) for (ll i = ((n) - 1); i >= (a); i--)
#define repd(i, n) repds(i, 0, (n))
#define rrepd(i, n) repds(i, 1, (n) + 1)
#define rep2(i, j, x, y) rep(i, x) rep(j, y)

template <typename T1, typename T2>
inline bool chmin(T1 &a, T2 b) {
    if (a > b) {
        a = b;
        return true;
    }
    return false;
}

template <typename T1, typename T2>
inline bool chmax(T1 &a, T2 b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}

#define LL(x) ll x;cin >> x;
#define VL(a,n) vl a(n);cin >> a;
#define AL(a,k) al<k> a;cin >> a;
#define VC(a,n) vc a(n);cin >> a;
#define VS(a,n) vs a(n);cin >> a;
#define STR(s) str s;cin >> s;
#define VPL(a,n) vpl a(n);cin >> a;
#define VAL(a,n,k) val<k> a(n);cin >> a;
#define VVL(a,n,m) vvl a(n,vl(m));cin >> a;
#define SL(a,n) sl a;{VL(b,n);a=sl(all(b));}

template <typename T>
using heap_max = priority_queue<T, vec<T>, less<T>>;
template <typename T>
using heap_min = priority_queue<T, vec<T>, greater<T>>;
#line 3 "main.cpp"

void solve() {
    LL(H);
    LL(W);
    VS(S, H);
    vvl X(H, vl(W));
    {
        vv<al<4>> tmp(H, val<4>(W, {-1, -1, -1, -1}));
        reps(i, 1, H) reps(j, 1, W) {
            if (S[i][j] == '.') continue;
            if (S[i - 1][j - 1] == '.') continue;
            tmp[i][j][0] = tmp[i - 1][j - 1][0] + 1;
            chmax(tmp[i][j][0], 1);
        }
        reps(i, 1, H) repd(j, W - 1) {
            if (S[i][j] == '.') continue;
            if (S[i - 1][j + 1] == '.') continue;
            tmp[i][j][1] = tmp[i - 1][j + 1][1] + 1;
            chmax(tmp[i][j][1], 1);
        }
        repd(i, H - 1) reps(j, 1, W) {
            if (S[i][j] == '.') continue;
            if (S[i + 1][j - 1] == '.') continue;
            tmp[i][j][2] = tmp[i + 1][j - 1][2] + 1;
            chmax(tmp[i][j][2], 1);
        }
        repd(i, H - 1) repd(j, W - 1) {
            if (S[i][j] == '.') continue;
            if (S[i + 1][j + 1] == '.') continue;
            tmp[i][j][3] = tmp[i + 1][j + 1][3] + 1;
            chmax(tmp[i][j][3], 1);
        }
        rep2(i, j, H, W) {
            X[i][j] = *min_element(all(tmp[i][j]));
        }
    }
    vvl ans(H, vl(W));
    {
        vpl c;
        rep(i, H) {
            c.push_back({i, 0});
        }
        rep(j, W) {
            c.push_back({0, j});
        }
        ll t = -1;
        for (auto [i, j] : c) {
            while (true) {
                if (i < 0) break;
                if (i >= H) break;
                if (j < 0) break;
                if (j >= W) break;
                chmax(t, X[i][j]);
                if (t >= 0) {
                    ans[i][j] = 1;
                }
                t--;
                i++;
                j++;
            }
        }
    }
    {
        vpl c;
        rep(i, H) {
            c.push_back({i, W - 1});
        }
        rep(j, W) {
            c.push_back({0, j});
        }
        ll t = -1;
        for (auto [i, j] : c) {
            while (true) {
                if (i < 0) break;
                if (i >= H) break;
                if (j < 0) break;
                if (j >= W) break;
                chmax(t, X[i][j]);
                if (t >= 0) {
                    ans[i][j] = 1;
                }
                t--;
                i++;
                j--;
            }
        }
    }
    {
        vpl c;
        rep(i, H) {
            c.push_back({i, 0});
        }
        rep(j, W) {
            c.push_back({H - 1, j});
        }
        ll t = -1;
        for (auto [i, j] : c) {
            while (true) {
                if (i < 0) break;
                if (i >= H) break;
                if (j < 0) break;
                if (j >= W) break;
                chmax(t, X[i][j]);
                if (t >= 0) {
                    ans[i][j] = 1;
                }
                t--;
                i--;
                j++;
            }
        }
    }
    {
        vpl c;
        rep(i, H) {
            c.push_back({i, W - 1});
        }
        rep(j, W) {
            c.push_back({H - 1, j});
        }
        ll t = -1;
        for (auto [i, j] : c) {
            while (true) {
                if (i < 0) break;
                if (i >= H) break;
                if (j < 0) break;
                if (j >= W) break;
                chmax(t, X[i][j]);
                if (t >= 0) {
                    ans[i][j] = 1;
                }
                t--;
                i--;
                j--;
            }
        }
    }
    rep2(i, j, H, W) {
        if (S[i][j] == '#' and ans[i][j] == 0) {
            print("No");
            return;
        }
    }
    print("Yes");
}

int main() {
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    solve();
}