There is a GRAY CODE game at http://www.html5pcode.com/a1ygraycode.htm The game uses a p-code. The p-code was written in HTML5 JavaScript.
The home page is http://www.html5pcode.com
You are to maximize the INCOME given a set of PRICES, REQUIREMENTS, and LIMITS. There are 4 products you can make with 4 materials. You enter the QUANTITY to make for each product. The QUANTITY must be an integer value. You can not exceed the limits on the materials. You can ask for the program solution to the game. It will use the GRAY CODE sequence of binary numbers to solve the game. There are 100 different games.
This game is written in a p-code. The p-code is executed by a p-code engine. If you click on PROGRAM in the RED STRIPE at the top, you can view the p-code programs. The p-code engine can execute the programs and it can edit the programs.There is a DATA option that allows you to see the program's data as it is being executed. There is a TRAIL option that allows you to execute the program in small steps. There is an RT, Real Time, option that allows you to change the program as it is executing. There are many YouTube videos that will show you how it works.