#include <iostream>
#include <cstdio>
using namespace std;
char s[51][52];

bool f(int i,int j)
{
    if(s[i][j]!='#')
        return true;
    else
        return false;
}

int main()
{
    int h,w,i,j,fg=1;
    cin>>h>>w;
    for(int i=0; i<h; i++)
        for(int j=0; j<w; j++)
            cin>>s[i][j];
    for(i=0; i<h; i++)
        for(j=0; j<w; j++)
        {
            if(s[i][j]=='#')
            {
                if(0<i&&i<h-1)
                {
                    if(0<j&&j<w-1)
                    {
                        if(f(i,j+1)&&f(i,j-1)&&f(i+1,j)&&f(i-1,j))
                        {
                            cout<<"No";
                            fg=0;
                            return 0;
                        }
                    }
                    else if(j==0)
                    {
                        if(f(i,j+1)&&f(i+1,j)&&f(i-1,j))
                        {
                            cout<<"No";
                            fg=0;
                            return 0;
                        }
                    }
                    else if(j==w-1)
                    {
                        if(f(i,j-1)&&f(i+1,j)&&f(i-1,j))
                        {
                            cout<<"No";
                            fg=0;
                            return 0;
                        }
                    }
                }
                if(i==0)
                {
                    if(0<j&&j<w-1)
                    {
                        if(f(i,j+1)&&f(i,j-1)&&f(i+1,j))
                        {
                            cout<<"No";
                            fg=0;
                            return 0;
                        }
                    }
                    else if(j==0)
                    {
                        if(f(i,j+1)&&f(i+1,j))
                        {
                            cout<<"No";
                            fg=0;
                            return 0;
                        }
                    }
                    else if(j==w-1)
                    {
                        if(f(i,j-1)&&f(i+1,j))
                        {
                            cout<<"No";
                            fg=0;
                            return 0;
                        }
                    }
                }
                if(i==h-1)
                {
                    if(0<j&&j<w-1)
                    {
                        if(f(i,j+1)&&f(i,j-1)&&f(i-1,j))
                        {
                            cout<<"No";
                            fg=0;
                            return 0;
                        }
                    }
                    else if(j==0)
                    {
                        if(f(i,j+1)&&f(i-1,j))
                        {
                            cout<<"No";
                            fg=0;
                            return 0;
                        }
                    }
                    else if(j==w-1)
                    {
                        if(f(i,j-1)&&f(i-1,j))
                        {
                            cout<<"No";
                            fg=0;
                            return 0;
                        }
                    }
                }

            }
        }
    if(fg)cout<<"Yes";
    return 0;
}











Measured memory_bytes: 256