h, w = map(int, input().split())
S = ['']*h
for i in range(h):
    S[i] = input()

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