h, w = list(map(int, input().split()))
s = [list(input()) for i in range(h)]
ss = [["." for i in range(w+2)] for j in range(h+2)]

for i in range(w):
    for j in range(h):
        ss[i+1][j+1]=s[i][j]

flag = 1

for i in range(h):
    for j in range(w):
        if ss[i+1][j+1]=="#":
            if ss[i][j+1]=="." and ss[i+2][j+1]=="." and ss[i+1][j]=="." and ss[i+1][j+2]==".":
                flag = 0
                break
                
if flag==1:
    print("Yes")
else:
    print("No")