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

s1=[['.' for i in range(h+2)] for i in range(w+2)]

for i in range(h):
    for j in range(w):
        if s[i][j]=='#':
            s1[i+1][j+1]='#'
for i in range(h+2):
    for j in range(w+2):
        if s1[i][j]=='#':
            if s1[i-1][j]==s1[i+1][j]==s1[i][j-1]==s1[i][j+1]=='.':
                print('No')
                exit()
print('Yes')