Make one prediction
Choose valid or invalid for the displayed group under our stated profile. The first answer locks the question, so feedback remains attached to your actual choice.
Read the reason
The explanation identifies a natural pattern, an allowed substitute or a failed requirement. A correct guess is not the same as a method you can repeat. Try saying why the result follows from these exact cards.
Review all six
The end screen keeps the question, wild setting, your answer and the explanation until restart or reload. Pick one assumption to change next time; there is no ranking or saved learning account.
Take it to paper
Use the exercise sheet to write a nearby example with one card changed. The page is a learning aid, not a certificate or measure of playing strength.