#include<stdio.h>
#include<string.h>
#include<math.h>
#include<algorithm>
using namespace std;
int main()
{
    char a[100][100];
    int n,m,i,j,flag;
    while(scanf("%d%d",&n,&m)==2)
    {
        flag=1;
        for(i=0;i<n;i++)
        {
            scanf("%s",a[i]);
        }
        for(i=0;i<n;i++)
        {
            for(j=0;j<m;j++)
            {
                if(a[i][j]=='#')
                {
                    flag=0;
                    if(j==0||j==m-1)
                    {
                        if(j==0)
                        {
                            if(i==0||i==n-1)
                            {
                                if(i==0)
                                {
                                    if(a[i+1][j]=='#'||a[i][j+1]=='#')
                                        flag=1;
                                }
                                else
                                {
                                    if(a[i-1][j]=='#'||a[i][j+1]=='#')
                                        flag=1;
                                }
                            }
                            else
                            {
                                if(a[i+1][j]=='#'||a[i-1][j]=='#'||a[i][j+1]=='#')
                                    flag=1;
                            }
                        }
                        else
                        {
                            if(i==0||i==n-1)
                            {
                                if(i==0)
                                {
                                    if(a[i+1][j]=='#'||a[i][j-1]=='#')
                                        flag=1;
                                }
                                else
                                {
                                    if(a[i][j-1]=='#'||a[i-1][j]=='#')
                                        flag=1;
                                }
                            }
                            else
                            {
                                if(a[i][j-1]=='#'||a[i+1][j]=='#'||a[i-1][j]=='#')
                                    flag=1;
                            }
                        }
                    }
                    else
                    {
                        if(i==0||i==n-1)
                        {
                            if(i==0)
                            {
                                if(a[i+1][j]=='#'||a[i][j+1]=='#'||a[i][j-1]=='#')
                                    flag=1;
                            }
                            else
                            {
                                if(a[i-1][j]=='#'||a[i][j+1]=='#'||a[i][j-1]=='#')
                                    flag=1;
                            }
                        }
                        else
                        {
                            if(a[i+1][j]=='#'||a[i][j+1]=='#'||a[i][j-1]=='#'||a[i-1][j]=='#')
                                flag=1;
                        }
                    }
                }
                if(flag==0)
                    break;
            }
            if(flag==0)
                break;
        }
        if(flag)
            printf("Yes\n");
        else
            printf("No\n");
    }
    return 0;
}


Measured memory_bytes: 128