#include<iostream>
using namespace std;
int main()
{
int h,w,i,j;
char c;
cin>>h>>w;
bool p[h][w];
for(i=0;i<h;i++)
{
for(j=0;j<w;j++)
{
cin>>c;
if(c=='.')p[i][j]=false;
else p[i][j]=true;
}}
for(i=0;i<h;i++)
{
for(j=0;j<w;j++)
{
if(p[i][j]==false)continue;
if((i!=0)&&(p[i-1][j]==true))continue;
if((i!=h)&&(p[i+1][j]==true))continue;
if((j!=0)&&(p[i][j-1]==true))continue;
if((j!=w)&&(p[i][j+1]==true))continue;
cout<<"No";
return 0;
}}
cout<<"Yes";
return 0;
}