Boardgamegeek https://boardgamegeek.com/boardgameexpansion/287988/ganz-schon-clever-challenge-i
English - A new sheet layout, similar (but not identical) to "Challenge II" offered in the Ganz Schon Clever app. This challenge changes the constraints and bonuses of each section, while keeping all the rules of the base game. The differences from the app include: No extra points for marking all 12 blue cells. No fox in the sixth reroll circle.
Official https://www.pixiegames.fr/roll-write/306-tres-fute-bloc-challenge-1-4001504493639.html
French - Ceci est une extension, nécessite le jeu de base.
Ludovox https://ludovox.fr/jeu-de-societe/tres-fute-challenge/
French - Renouvelez le défi proposé par le jeu de base, avec des variations sur les pouvoirs et des scorings proposés.