O
____
2 ↓ | ___| ←1 ↓3
_______ _________ __
|_______||_________||__| ↓4
____________ __ _______
| ||__|_______|
|____________||_______| ←5
_________ 7↓_____| |
8→| | | | |
|_________| |_____| | | ←6
10→| | 9→| | |
|_________| |__ ___| |
|_________| |__||__||__|
最底得番3個是但