
def main():
	line = input()
	vector = [int(x) for x in line.split()]
	n = vector[0]
	m = vector[1]
	matrix = [ [] for i in range(m)]
	for i in range(n):
		line = input()
		for c in line:
			matrix[i].append(c)
			
	ok = "Yes"
	for i in range(n):
		for j in range(m):
			okUp = 0
			okLeft = 0
			okRight = 0
			okDown = 0
			if matrix[i][j] == '#':
				if i > 0:
					if matrix[i-1][j] == '#':
						okUp = 1
				if j > 0:
					if matrix[i][j - 1] == '#':
						okLeft = 1
				if i < n - 1:
					if matrix[i+1][j] == '#':
						okDown = 1
				if j < m - 1:
					if matrix[i][j + 1] == '#':
						okRight = 1
				if okRight == 0 and okDown == 0 and okLeft == 0 and okUp == 0:
					print("No")
					return
	
	print("Yes")
 
 
 
if __name__ == "__main__":
	main()