import sys
H,W = map(int,input().split())
temp =[0 for i in range(H)]
now_point = [0,0]
for i in range(H):
    temp[i] = input()
dx = [-1,1,0,0]
dy = [0,0,1,-1]

for j in range(H*W):
    if temp[now_point[0]][now_point[1]] == "#":
        # temp_count1 = 0
        temp_count2 = 0
        for i in range(4):
            serch_point = [now_point[0]+dx[i],now_point[1]+dy[i]]
            if 0 <= serch_point[0] < H and 0 <= serch_point[1] < W:
                    # temp_count += 1
                if temp[serch_point[0]][serch_point[1]] == "#":   
                    temp_count2 += 1
        # if temp_count1 == temp_count2:
        if temp_count2 == 0:
            print("No")
            sys.exit()
print("Yes")
