hw = input().split(" ");
h = int(hw[0]);
w = int(hw[1]);
pic = [['.']*(h+2) for i in range(w+2)];
can = 0;
for i in range(1,h+1) :
	s = list(input().rstrip('\n'));
	for j in range(1,w+1) :
		pic[i][j] = s[j-1];
for i in range(1,h+1) :
	for j in range(1,w+1) :
		if pic[i][j] == '#' and pic[i][j-1] == '.' and pic[i-1][j] == '.' and pic[i][j+1] == '.' and pic[i+1][j] == '.' :
			can = can + 1;
if can == 0 :
	print('Yes');
else :
	print('No');