ChangeChangeRules

Change Change is a solo game created by Sid Sackson. It uses 11 coins of four different denominations. This description assumes four pennies, four nickels, two dimes and one quarter, but any combination of values may be used.

Setup

Shake the 11 coins in your hand and place them in a 4×3 grid on a table or other flat surface, leaving one space empty. In the diagram below, the O’s represent coins and the X represents the empty cell.

O O O O
O O O O
O O O X

The objective is to rearrange the coins into a symmetrical position by sliding them one at a time into the empty cell. Only a coin directly next to the empty cell, not diagonally, may be moved into it.

A symmetrical position is balanced around the middle row. For example, if a penny is in the top row, there must be another penny directly below it in the bottom row. The single coin and the empty cell must always end up in the middle row.

Sample game

In recording a game, the 12 cells are lettered thus:

A B C D
E F G H
I J K L

Because there is only one place a moved coin can go, one only needs to record the starting cell. Here is a sample arrangement of coins (numbers should be replaced by actual U.S. coin images):

(25) (10) (1) (10)
 (1)  (5) (5) (10)
 (1) (10) (1)  (X)

This arrangement can be solved in 24 moves: K, J, F, E, I, J, F, G, C, B, F, E, A, B, C, G, K, L, H, G, F, B, C, G.

This is the symmetrical position:

 (5)  (1) (1) (10)
(25) (10) (X) (10)
 (5)  (1) (1) (10)

Winning

Play seven games, keeping track of the number of moves needed to reach a symmetrical position in each. If you can complete the seven games in 100 moves or fewer, you win.