h,w = map(int, input().split())
# print(h,w)
row = []
for x in range(h):
    col = list(input())
    row.append(col)

out = "YES"

for x in range(h):
    for y in range (w):
        if row[x][y] == "#":
           #print(x,y)
            if  x > 0 and row[x-1][y] == "#":
                pass
            elif x < h-1 and row[x+1][y] == "#":
                pass
            elif y > 0 and row[x][y-1] == "#" :
                pass
            elif y < w-1  and row [x][y+1] == "#" :
                pass
            else:
                out = "NO"
                break
        pass

print(out)