Add a rule named Color Coding:

Squares may be color coded with one or more colors. Each color code shall be represented in the [[Word]] besides the name of the Squares by two letters.

At any time, if a Square has no color code, it gains the White color code. At any time, if a White Square gains another color code, it loses the White color.

If a Square is mentioned by name in a rule, that square gains the Gray color code. If a Gray Square is not mentioned by name in any rule, it loses the Gray color code.

Currently, the possible color codes are:
* Bk - Black
* Gr - Gray
* Wh - White
* Bl - Blue
* Rd - Red
* Yl - Yellow

Give squares “Go”, “Jackpot” and “Throne” a Gray color code. Give all other squares a White color code.