h,w = input().split()
H = int(h)
W = int(w)

list_masu = []

for i in range(H):
	str1 = str(input())
	charlist = list(str1)
	list_masu.append(charlist)

blacklist = []
for n in range(H):
	for m in range(W):
		if(list_masu[n][m]=="#"):
			blacklist.append((n,m))

blacklist.sort()

count = 0

for b in range(0,len(blacklist)):
	for i in range(0,len(blacklist)-1):
		if(b!=i and blacklist[b][0] == blacklist[i][0]):
			if((blacklist[b][1] == blacklist[i][1]+1) or (blacklist[b][1]+1 == blacklist[i][1])):
				count += 1
				break
		elif(b!=i and blacklist[b][1] == blacklist[i][1]):
			if((blacklist[b][0] == blacklist[i][0]+1) or (blacklist[b][0]+1 == blacklist[i][0])):
				count += 1
				break


if(count==len(blacklist)):
	print("Yes")
else:
	print("No")