h, w = map(int, input().split())

s = [list(input()) for _ in range(h)]

DX = [-1, 0, 1, 0]
DY = [0, -1, 0, 1]

ans = True

for i in range(h):
    for j in range(w):
        if s[i][j] == ".":
            continue
        flag = 0
        for k in range(4):    
            if not(0<=i+DX[k]<=w and 0<=j+DY[k]<=h):
                continue
            if s[i + DX[k]][j + DY[k]] == "#":
                flag = 1
                break
        if flag == 0:
          ans = False
          break
print("Yes" if ans else "No")
