I created a similar code system long time ago but never published it because its operational system was really rude a resource consuming.
I improved that version into this one that operates solo on mathematical operations and logic entities, not using doors as transistors as the old one did.
Prefab room with a code system that allows random code generation or user input and display's it on a display screen.
Has a 9 digit keypad to set the code or input one for verification that displays the result of it.
Also the display has counter functionality with adding and subtraction capability.
Can be used to implement some dynamic functionality over rounds on CSS maps.