H,W=map(int,input().split())
s=[list(input()) for i in range (H)] 
import sys
for j in range (2,W):
    for k in range (2,H-1):
        if s[j][k-2:k+1]==['#', '.', '#'] and s[j-2:j+1][k]==['#', '.', '#']:
            print ('No')
            sys.exit()