#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (n); i++)
#define per(i, n) for (int i = (n)-1; i >= 0; i--)
#define rep2(i, l, r) for (int i = (l); i < (r); i++)
#define per2(i, l, r) for (int i = (r)-1; i >= (l); i--)
#define each(e, v) for (auto &e : v)
#define MM << " " <<
#define pb push_back
#define eb emplace_back
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
#define sz(x) (int)x.size()
using ll = long long;
using pii = pair<int, int>;
using pil = pair<int, ll>;
using pli = pair<ll, int>;
using pll = pair<ll, ll>;

template <typename T>
using minheap = priority_queue<T, vector<T>, greater<T>>;

template <typename T>
using maxheap = priority_queue<T>;

template <typename T>
bool chmax(T &x, const T &y) {
    return (x < y) ? (x = y, true) : false;
}

template <typename T>
bool chmin(T &x, const T &y) {
    return (x > y) ? (x = y, true) : false;
}

template <typename T>
int flg(T x, int i) {
    return (x >> i) & 1;
}

int pct(int x) { return __builtin_popcount(x); }
int pct(ll x) { return __builtin_popcountll(x); }
int topbit(int x) { return (x == 0 ? -1 : 31 - __builtin_clz(x)); }
int topbit(ll x) { return (x == 0 ? -1 : 63 - __builtin_clzll(x)); }
int botbit(int x) { return (x == 0 ? -1 : __builtin_ctz(x)); }
int botbit(ll x) { return (x == 0 ? -1 : __builtin_ctzll(x)); }

template <typename T>
void print(const vector<T> &v, T x = 0) {
    int n = v.size();
    for (int i = 0; i < n; i++) cout << v[i] + x << (i == n - 1 ? '\n' : ' ');
    if (v.empty()) cout << '\n';
}

template <typename T>
void printn(const vector<T> &v, T x = 0) {
    int n = v.size();
    for (int i = 0; i < n; i++) cout << v[i] + x << '\n';
}

template <typename T>
int lb(const vector<T> &v, T x) {
    return lower_bound(begin(v), end(v), x) - begin(v);
}

template <typename T>
int ub(const vector<T> &v, T x) {
    return upper_bound(begin(v), end(v), x) - begin(v);
}

template <typename T>
void rearrange(vector<T> &v) {
    sort(begin(v), end(v));
    v.erase(unique(begin(v), end(v)), end(v));
}

template <typename T>
vector<int> id_sort(const vector<T> &v, bool greater = false) {
    int n = v.size();
    vector<int> ret(n);
    iota(begin(ret), end(ret), 0);
    sort(begin(ret), end(ret), [&](int i, int j) { return greater ? v[i] > v[j] : v[i] < v[j]; });
    return ret;
}

template <typename T>
void reorder(vector<T> &a, const vector<int> &ord) {
    int n = a.size();
    vector<T> b(n);
    for (int i = 0; i < n; i++) b[i] = a[ord[i]];
    swap(a, b);
}

template <typename T>
T floor(T x, T y) {
    assert(y != 0);
    if (y < 0) x = -x, y = -y;
    return (x >= 0 ? x / y : (x - y + 1) / y);
}

template <typename T>
T ceil(T x, T y) {
    assert(y != 0);
    if (y < 0) x = -x, y = -y;
    return (x >= 0 ? (x + y - 1) / y : x / y);
}

template <typename S, typename T>
pair<S, T> operator+(const pair<S, T> &p, const pair<S, T> &q) {
    return make_pair(p.first + q.first, p.second + q.second);
}

template <typename S, typename T>
pair<S, T> operator-(const pair<S, T> &p, const pair<S, T> &q) {
    return make_pair(p.first - q.first, p.second - q.second);
}

template <typename S, typename T>
istream &operator>>(istream &is, pair<S, T> &p) {
    S a;
    T b;
    is >> a >> b;
    p = make_pair(a, b);
    return is;
}

template <typename S, typename T>
ostream &operator<<(ostream &os, const pair<S, T> &p) {
    return os << p.first << ' ' << p.second;
}

struct io_setup {
    io_setup() {
        ios_base::sync_with_stdio(false);
        cin.tie(NULL);
        cout << fixed << setprecision(15);
        cerr << fixed << setprecision(15);
    }
} io_setup;

constexpr int inf = (1 << 30) - 1;
constexpr ll INF = (1LL << 60) - 1;
// constexpr int MOD = 1000000007;
constexpr int MOD = 998244353;

void solve() {
    int H, W;
    cin >> H >> W;

    vector<string> S(H);
    rep(i, H) cin >> S[i];

    vector<int> dx = {1, 0, -1, 0}, dy = {0, 1, 0, -1};
    auto IN = [&](int i, int j) { return 0 <= i && i < H && 0 <= j && j < W && S[i][j] == '#'; };
    auto ENUM = [&](int x, int y) {
        vector<pii> ret;
        rep(k, 4) {
            int nx = x + dx[k], ny = y + dy[k];
            if (IN(nx, ny)) ret.eb(nx, ny);
        }
        return ret;
    };

    vector<pii> p = {{1, 1}, {1, -1}, {-1, 1}, {-1, -1}};

    vector len(4, vector(H, vector(W, 0)));

    rep(k, 4) {
        auto [dx, dy] = p[k];
        if (dx == 1) {
            per(x, H) rep(y, W) {
                if (IN(x, y)) {
                    len[k][x][y] = 1;
                    if (IN(x + dx, y + dy)) len[k][x][y] += len[k][x + dx][y + dy];
                }
            }
        } else {
            rep(x, H) rep(y, W) {
                if (IN(x, y)) {
                    len[k][x][y] = 1;
                    if (IN(x + dx, y + dy)) len[k][x][y] += len[k][x + dx][y + dy];
                }
            }
        }
    }

    vector l(H, vector(W, inf));
    rep(i, H) rep(j, W) rep(k, 4) chmin(l[i][j], len[k][i][j]);

    vector ok(H, vector(W, 0));

    rep(k, 4) {
        vector dp(H, vector(W, 0));
        auto [dx, dy] = p[k];
        if (dx == 1) {
            rep(x, H) rep(y, W) {
                if (IN(x - dx, y - dy)) {
                    if (dp[x - dx][y - dy] >= 1) ok[x][y] = 1;
                    chmax(dp[x][y], dp[x - dx][y - dy] - 1);
                }
                if (l[x][y] >= 2) {
                    ok[x][y] = 1;
                    chmax(dp[x][y], l[x][y] - 1);
                }
            }
        } else {
            per(x, H) rep(y, W) {
                if (IN(x - dx, y - dy)) {
                    if (dp[x - dx][y - dy] >= 1) ok[x][y] = 1;
                    chmax(dp[x][y], dp[x - dx][y - dy] - 1);
                }
                if (l[x][y] >= 2) {
                    ok[x][y] = 1;
                    chmax(dp[x][y], l[x][y] - 1);
                }
            }
        }
    }

    // rep(i, H) print(ok[i]);

    rep(x, H) rep(y, H) {
        if (IN(x, y) && ok[x][y] == 0) {
            cout << "No\n";
            return;
        }
    }

    cout << "Yes\n";

    // auto judge = [&](int i, int j) {
    //     if (!IN(i, j)) return false;
    //     if (!IN(i + 1, j - 1)) return false;
    //     if (!IN(i + 1, j + 1)) return false;
    //     if (!IN(i - 1, j - 1)) return false;
    //     if (!IN(i - 1, j + 1)) return false;
    //     return true;
    // };

    // rep(i, H) rep(j, W) {
    //     if (S[i][j] = '#') {
    //         bool f = judge(i, j);
    //         f |= judge(i + 1, j + 1);
    //         f |= judge(i + 1, j - 1);
    //         f |= judge(i - 1, j + 1);
    //         f |= judge(i - 1, j - 1);
    //         if (!f) {
    //             cout << "No\n";
    //             return;
    //         }
    //     }
    // }

    // cout << "Yes\n";
}

int main() {
    int T = 1;
    // cin >> T;
    while (T--) solve();
}