H,W = map(int,input().split())
List = [[""]*H]*W
for i in range(H):
    tmp = input()
    tmp = list(tmp)
    List[i] = tmp
for i in range(H):
    for j in range(W):
        if(List[i][j] == "#"):
            if(i == H-1):
                pass
            elif(j == W-1):
                pass
            else:
                if(List[i+1][j] == "#" or List[i][j+1] == "#" or List[i][j-1] == "#" or List[i-1][j-1] == "#"):
                    pass
                else:
                    print("No")
                    exit()
print("Yes")