#include <cstdio>
#include <queue>
#include <algorithm>
using namespace std;
int N,M;
char A[55][55];

int main()
{
	scanf("%d%d",&N,&M);
		for(int i=1;i<=N;i++)scanf("%s",A[i]+1);
		for(int i=1;i<=N;i++){
			for(int j=1;j<=M;j++){
				if(A[i][j]=='#'&&(A[i-1][j]=='.'||!(i-1))&&(A[i][j-1]=='.'||!(j-1))&&(A[i+1][j]=='.'||i+1>N)&&(A[i][j+1]=='.'||j+1>M))
					return puts("No"),0;
			}
		}
	puts("Yes");
	return 0;
}
