# -*- coding: utf-8 -*-

H,W = map(int, input().split())

s = []
for i in range(0,W):
    data = input()
    s.append(data)

result ="Yes"
check = 0

#1行目
for i in range(0,W):
    if s[0][i]=="#":
        if i==0:
            if s[1][i] == "." and s[0][i+1] == ".":
                result = "No"
                check = 1
                break
        elif i == W-1:
            if s[1][i] == "." and s[0][i-1] == ".":
                result = "No"
                check = 1
                break                
        else:        
            if s[1][i] == "." and s[0][i+1] == "." and s[0][i-1] == ".":
                result = "No"
                check = 1
                break


if check == 0:
    #H行目
    for i in range(0,W):
        if s[H-1][i]=="#":
            if i==0:
                if s[H-2][i] == "." and s[H-1][i+1] == ".":
                    result = "No"
                    check = 1
                    break
            elif i == W-1:
                if s[H-2][i] == "." and s[H-1][i-1] == ".":
                    result = "No"
                    check = 1
                    break                
            else:        
                if s[H-2][i] == "." and s[H-1][i+1] == "." and s[H-1][i-1] == ".":
                    result = "No"
                    check = 1
                    break
else:
    pass

if check == 0:
    for i in range(1,H-1):#行
        if check == 1:
            break       
        for j in range(0,W):#列
            if s[i][j]=="#":            
                if j==0:#左端
                    if s[i-1][j] == "." and s[i+1][j] == "." and s[i][j+1] == ".":
                        result = "No"
                        check = 1
                        break
                elif j == W-1:#右端
                    if s[i-1][j] == "." and s[i+1][j] == "." and s[i][j-1] == ".":
                        result = "No"
                        check = 1
                        break                
                else:        
                    if  s[i-1][j] == "." and s[i+1][j] == "." and s[i][j+1] == "." and s[i][j-1] == ".":
                        result = "No"
                        check = 1
                        break         
    
    
    print(result)
  
else:
    print(result)
        