# -*- coding: utf-8 -*-
h, w = map(int,input().split())
s = []
for i in range(w):
    s.append(list(input()))

ans = "Yes"
for i in range(h):
    for j in range(w):
        if s[i][j] == '#' and s[max(0,i - 1)][j] == '.' and s[min(h - 1, i + 1)][j] == '.' and s[i][min(w - 1, j + 1)] == '.' and s[i][max(0, j - 1)] == '.':
            ans = "No"
print(ans)
