I'm going to need someone to confirm my calculations here, but I

*think* I've worked out that adding random yellow cards to a lock actually helps the person playing the game.

Here's how I worked it out:

There are five types of yellow card -

- +1 red cards
- +2 red cards
- +3 red cards
- -1 red cards
- -2 red cards

On the face of it, it looks like random yellows aren't good news because there's more chance of encountering ones that add red cards, than ones that remove them. If you take an average of the five possibilities, you get +0.6 cards added to the deck.

However, the key element to this theory is that if you pick a yellow card, then once it has adjusted the number of red cards accordingly,

**you get to pick again immediately**. This means that 1 extra card is removed from your deck, and so the actual effect of a random yellow card is to reduce the number of cards in your deck by an average of 0.4.

If this theory is accurate, there are a few countermeasures that could be added to the app to resolve it:

- Adding a "+4 red cards" and/or "+5 red cards" yellow card
- Not allowing another card to be picked immediately after a yellow card
- Adding yellow cards that increase the number of freeze, reset, or double up cards (this would potentially have more drastic consequences and would need to be looked at more carefully)

Of course, this theory is only applicable to random yellow cards, if specific yellow cards are selected for a particular run, then these numbers can easily be manipulated accordingly.