You're going for too big cards again. A single card doesn't need to answer absolutely everything there is about a red black tree. You want to ask about a single

You're going for too big cards again. A single card doesn't need to answer absolutely everything there is about a red black tree. You want to ask about a single aspect of it per card. The definition is "what is it?". There is nothing to understand here. It could be taught to a parrot or child to repeat this information. What you're mentioning is a bunch of cards on top of that: how does a red black tree stay balanced on insertions? When is the self-balancing property of red black trees useful? When is it not? Etc etc. You cannot answer this if you mistake a red black tree for another tree for example. It's essentially vocabulary. Another one would be notations: what's the symbol for a cross product? Again, nothing to understand, but you must know it to work on actual math problems involving cross products.