Keep the declaration visible
The checker asks for the declared suit when the top card is an eight. Changing that declaration changes which ordinary candidates match. Another eight remains a wild option in this model.
A useful example
Try a top eight of hearts with spades declared. The demo separates what is printed on the card from the current matching suit. Read its explanation before changing the selection.
Boundaries
This is a basic matching demonstration. It does not include restrictions from a special-card variant, draw stacking or a complete game state.