_______________ _______________ _______________
| [x->2, y->3] | | [x->2, y->3] | | [x->2, y->3] |
------------------- ------------------ ------------------
| | ¢ | | = | |
| +2 | | y | | 5 |
|______________| |______________| |______________|
_______________ _______________ _______________
| [x->2, y->3] | | [x->2, y->3] | | [x->2, y->3] |
------------------- ------------------ ------------------
| | ¢ | | = | |
| +2 | | y | | 5 |
|______________| |______________| |______________|