import java.util.*;
import java.lang.Math;
class Main {
    public static void main(String[] args) {
      Scanner sc = new Scanner(System.in);
      int H = sc.nextInt();
      int W = sc.nextInt(); sc.nextLine(); //nextIntの後残る改行文字を消す
      String[] line = new String[W];
      int r=0;
      for(int i=0;i<W;i++){
      	line[i]=sc.nextLine();
      } 
      String[][] a = new String[H][W];
      String[][] b = new String[H+2][W+2];
         for(int j=0;j<W;j++){
          for(int k=0;k<H;k++){
           a[k][j]=String.valueOf(line[j].charAt(k));
           b[k+1][j+1]=a[k][j];
          }
         }

         for(int j=0;j<W+2;j++){
          for(int k=0;k<H+2;k++){
           b[0][j]=".";
           b[H+1][j]=".";
           b[k][0]=".";
           b[k][W+1]=".";
          }
         }
          
         for(int j=0;j<W+2;j++){
          for(int k=0;k<H+2;k++){
          if(b[k][j].equals("#")){
                   if(b[k+1][j].equals(".")&&b[k-1][j].equals(".")&&b[k][j+1].equals(".")&&b[k][j-1].equals(".")){
                                       r+=1;
                      }else{
                                       r+=0;
                       }
           }
          }
         }
           if(r>0){
                 System.out.println("No");
           }else{
                 System.out.println("Yes");      
           }
   }
}