#include <bits/stdc++.h>
#define re return
#define ll long long
#define ld long double
#define f first
#define s second
#define pi acos(-1)
#define oo (int)1e9
#define OO (ll)1e18
#define EPS 1e-7
#define FX(n) fixed<<setprecision(n)
#define mm(o,k) memset(o,k,sizeof o)
#define IO ios_base::sync_with_stdio(0),cin.tie(0),cout.tie(0);
using namespace std;
const int maxn=55;
int a[maxn][maxn];
int main()
{
    IO;
    int n,m;
    cin >> n >> m;
    for(int i=0;i<n;++i){
        for(int j=0;j<m;++j){
            char x;
            cin >> x;
            a[i][j]=x=='.';
        }
    }
    for(int i=1;i<n-1;++i)
        for(int j=1;j<m-1;++j)
            if(!a[i][j]&&a[i][j+1]&&a[i][j-1]&&a[i+1][j]&&a[i-1][j])exit(puts("No"));
    puts("Yes");
    re 0;
}
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