#include<bits/stdc++.h>
using namespace std;
int main()
{
	int h,w;
	cin>>h>>w;
	char a[h+2][w+2];
	for (int i=0;i<=h+1;++i)
	for (int i=1;i<=h;i++)
	{
	for (int j=1;j<=w;++j)
	{
		cin>>a[i][j];
	}
	}
	for (int i=1;i<=h+1;i++)
	{
		for (int j=1;j<=w+1;++j)
		a[i][j]=".";
		{
			if (a[i][j]=="#"&&a[i+1][j]!="#"&&a[i-1][j]!="#"&&a[i][j-1]!="#"&&a[i][j+1]!="#")
			{
				cout<<"No";
			}
		}
	}
	cout<<"Yes";
	return 0;
}