#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
istream &operator>>(istream &is, modint &a) { long long v; is >> v; a = v; return is; }
ostream &operator<<(ostream &os, const modint &a) { return os << a.val(); }
istream &operator>>(istream &is, modint998244353 &a) { long long v; is >> v; a = v; return is; }
ostream &operator<<(ostream &os, const modint998244353 &a) { return os << a.val(); }
istream &operator>>(istream &is, modint1000000007 &a) { long long v; is >> v; a = v; return is; }
ostream &operator<<(ostream &os, const modint1000000007 &a) { return os << a.val(); } 

typedef long long ll;
typedef vector<vector<int>> Graph;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define FOR(i,l,r) for (int i = l;i < (int)(r); i++)
#define rep(i,n) for (int i = 0;i < (int)(n); i++)
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define my_sort(x) sort(x.begin(), x.end())
#define my_max(x) *max_element(all(x))
#define my_min(x) *min_element(all(x))
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; }
const int INF = (1<<30) - 1;
const ll LINF = (1LL<<62) - 1;
const int MOD = 998244353;
const int MOD2 = 1e9+7;
const double PI = acos(-1);
vector<int> di = {1,-1,1,-1};
vector<int> dj = {1,1,-1,-1};

#ifdef LOCAL
#  include <debug_print.hpp>
#  define debug(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__)
#else
#  define debug(...) (static_cast<void>(0))
#endif

int main(){
    cin.tie(0);
    ios_base::sync_with_stdio(false);
    int H, W; cin >> H >> W;
    vector<string> S(H);
    rep(i,H) cin >> S[i];

    vector wa1(H, vector<int>(W, 0)); // (i, j) <- (i - 1, j - 1);
    for(int i = 0; i < H; i++){
        for(int j = 0; j < W; j++){
            if(S[i][j]!='#')continue;
            if(i > 0 && j > 0) wa1[i][j] = wa1[i - 1][j - 1] + 1;
            else wa1[i][j] = 1;
        }
    }
    debug(wa1);

    vector wa2(H, vector<int>(W, 0)); // (i, j) <- (i - 1, j + 1);
    for(int i = 0; i < H; i++){
        for(int j = W - 1; j >= 0; j--){
            if(S[i][j]!='#')continue;
            if(i > 0 && j < W - 1) wa2[i][j] = wa2[i - 1][j + 1] + 1;
            else wa2[i][j] = 1;
        }
    }
    debug(wa2);

    vector wa3(H, vector<int>(W, 0)); // (i, j) <- (i + 1, j - 1);
    for(int i = H - 1; i >= 0; i--){
        for(int j = 0; j < W; j++){
            if(S[i][j]!='#')continue;
            if(i < H - 1 && j > 0) wa3[i][j] = wa3[i + 1][j - 1] + 1;
            else wa3[i][j] = 1;
        }
    }
    debug(wa3);

    vector wa4(H, vector<int>(W, 0)); // (i, j) <- (i + 1, j + 1);
    for(int i = H - 1; i >= 0; i--){
        for(int j = W - 1; j >= 0; j--){
            if(S[i][j]!='#')continue;
            if(i < H - 1 && j < W - 1) wa4[i][j] = wa4[i + 1][j + 1] + 1;
            else wa4[i][j] = 1;
        }
    }
    debug(wa4);

    vector imos1(H + 1, vector<int>(W + 1)); // (i, j) -> (i + 1, j + 1);
    vector imos2(H + 1, vector<int>(W + 1)); // (i, j) -> (i + 1, j - 1);
    rep(i,H)rep(j,W)if(S[i][j]=='#'){
        int d = 1 << 30;
        chmin(d, wa1[i][j]);
        chmin(d, wa2[i][j]);
        chmin(d, wa3[i][j]);
        chmin(d, wa4[i][j]);
        d--;
        if(d==0)continue;
        debug(i, j, d);

        imos1[i - d][j - d]++;
        imos1[i + d + 1][j + d + 1]--;
        imos2[i - d][j + d]++;
        if(j - d - 1 >= 0) imos2[i + d + 1][j - d - 1]--;
    }
    debug(imos1, imos2);

    for(int i = 0; i < H; i++){
        for(int j = 0; j < W; j++){
            imos1[i + 1][j + 1] += imos1[i][j];
        }
    }
    for(int i = 0; i < H; i++){
        for(int j = W; j > 0; j--){
            imos2[i + 1][j - 1] += imos2[i][j];
        }
    }
    debug(imos1, imos2);

    rep(i,H)rep(j,W)if(S[i][j]=='#'){
        if(imos1[i][j]==0&&imos2[i][j]==0){
            cout << "No" << endl;
            return 0;
        }
    }
    cout << "Yes" << endl;
}