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