h,w=map(int,input().split())
s=[list(map(int,list(input()))) for i in range(h)] 

for i in range(1,h-1):
    for j in range(1,w-1):
        if s[i][j]=='#':
            if s[i-1][j]=='.' and s[i][j-1]=='.' and s[i][j+1]=='.' and s[i+1][j]=='.':
                print('No')
                exit()
print('Yes')