#include "bits/stdc++.h"
using namespace std;

#define REP(i, n) for(ll i = 0;i < n;i++)
#define REPR(i, n) for(ll i = n;i >= 0;i--)
#define FOR(i, m, n) for(ll i = m;i < n;i++)
#define FORR(i, m, n) for(ll i = m;i >= n;i--)
#define REPO(i, n) for(ll i = 1;i <= n;i++)
#define ll long long
#define INF (ll)1ll << 60
#define MINF (-1 * INF)
#define ALL(n) n.begin(),n.end()
#define MOD (ll)1000000007
#define P pair<ll, ll>

ll h, w;
vector<string> s;
vector<vector<ll>> v[4], r[4];
bool check(ll x, ll y){
    if(0 <= x and x < h and 0 <= y and y < w) return true;
    return false;
}
void solve(ll num, ll x0, ll y0, ll dx1, ll dy1, ll dx2, ll dy2, ll dx, ll dy){
    ll x = x0, y = y0;
    while(1){
        ll nx = x, ny = y, now = 0;
        while(1){
            if(s[nx][ny] == '#'){
                now++;
            }
            else now = 0;
            v[num][nx][ny] = now;
            if(!check(nx + dx, ny + dy))break;
            nx += dx;
            ny += dy;
        }
        if(!check(x + dx1, y + dy1))break;
        x += dx1;
        y += dy1;
    }
    x += dx2;
    y += dy2;
    if(!check(x + dx2, y + dy2))return;
    while(1){
        ll nx = x, ny = y, now = 0;
        while(1){
            if(s[nx][ny] == '#'){
                now++;
            }
            else now = 0;
            v[num][nx][ny] = now;
            if(!check(nx + dx, ny + dy))break;
            nx += dx;
            ny += dy;
        }
        if(!check(x + dx2, y + dy2))break;
        x += dx2;
        y += dy2;
    }
}

void solve2(ll num, ll x0, ll y0, ll dx1, ll dy1, ll dx2, ll dy2, ll dx, ll dy){
    ll x = x0, y = y0;
    while(1){
        ll nx = x, ny = y, now = 0;
        while(1){
            now = max(now - 1, r[num][nx][ny]);
            r[num][nx][ny] = now;
            if(!check(nx + dx, ny + dy))break;
            nx += dx;
            ny += dy;
        }
        if(!check(x + dx1, y + dy1))break;
        x += dx1;
        y += dy1;
    }
    x += dx2;
    y += dy2;
    if(!check(x + dx2, y + dy2))return;
    while(1){
        ll nx = x, ny = y, now = 0;
        while(1){
            now = max(now - 1, r[num][nx][ny]);
            r[num][nx][ny] = now;
            if(!check(nx + dx, ny + dy))break;
            nx += dx;
            ny += dy;
        }
        if(!check(x + dx2, y + dy2))break;
        x += dx2;
        y += dy2;
    }
}

int main(){
    cin >> h >> w;
    s.resize(h);
    REP(i, 4) v[i].resize(h, vector<ll>(w));
    REP(i, 4) r[i].resize(h, vector<ll>(w));
    REP(i, h)cin >> s[i];
    solve(0, 0, w - 1, 0, -1, 1, 0, 1, 1);
    solve(1, 0, 0, 0, 1, 1, 0, 1, -1);
    solve(2, h - 1, 0, 0, 1, -1, 0, -1, -1);
    solve(3, 0, 0, 1, 0, 0, 1, -1, 1);
    REP(i, h){
        REP(j, w){
            ll now = INF;
            REP(k, 4)now = min(now, v[k][i][j]);
            if(now >= 2){
                REP(k, 4) r[k][i][j] = now;
            }
        }
    }
    solve2(0, 0, w - 1, 0, -1, 1, 0, 1, 1);
    solve2(1, 0, 0, 0, 1, 1, 0, 1, -1);
    solve2(2, h - 1, 0, 0, 1, -1, 0, -1, -1);
    solve2(3, 0, 0, 1, 0, 0, 1, -1, 1);

    REP(i, h){
        REP(j, w){
            ll now = 0;
            REP(k, 4)now = max(now, r[k][i][j]);
            if(now == 0 and s[i][j] == '#'){
                cout <<"No" << endl;
                return 0;
            }
        }
    }
    cout <<"Yes"<<endl;
}