#include <bits/stdc++.h>
using namespace std;

int main(){
  int h,w;
  int  han=0;
  cin >> h >> w; char cam[h][w];
  for(int i=0;i<h;i++) for(int j=0;j<w;j++) cin >> cam[i][j];
  if(h==1&&w==1) {
    if(cam[i][j]=='#') cout << "Yes" << endl;
    else cout << "No" << endl;
    exit(0);
  }
  for(int i=0;i<h;i++){
    for(int j=0;j<w;j++){
      if(cam[i][j]=='#'){
        if(i==0&&j==0) if(cam[i+1][j]!='#'&&cam[i][j+1]!='#') han=1;
        else if(i==h-1&&j==w-1) if(cam[i-1][j]!='#'&&cam[i][j-1]!='#') han=1;
        else if(j==0) if(cam[i+1][j]!='#'&&cam[i][j+1]!='#'&&cam[i-1][j]!='#') han=1;
        else if(i==0) if(cam[i][j-1]!='#'&&cam[i+1][j]!='#'&&cam[i][j+1]!='#') han=1;
        else if(j==w-1) if(cam[i-1][j]!='#'&&cam[i][j-1]!='#'&&cam[i+1][j]!='#') han=1;
        else if(i==h-1) if(cam[i-1][j]!='#'&&cam[i][j-1]!='#'&&cam[i][j+1]!='#') han=1;
        else if(cam[i-1][j]!='#'&&cam[i+1][j]!='#'&&cam[i][j-1]!='#'&&cam[i][j+1]!='#') han=1;
      }
    }
    if(han==1) {
      cout << "No" << endl;
      exit(0);
    }
  }
  cout << "Yes" << endl;
}