import sys
h,w = map(int,input().split())
a = ["."*(w+2)]+['.'+input()+'.' for i in range(h)]+["."*(w+2)]
for i in range(h):
    for j in range(w):
        if a[i][j+1] != "#" and a[i+1][j] != "#" and a[i+1][j+2]  != "#" and a[i+2][j+1] != "#":
            print("No")
            sys.exit()
print("Yes")
