Maximum Setless Collections
Top: A proposed 21-card collection which contains no sets.
Bottom: A 9-card collection from the 27-card deck which contains no sets.
The bottom collection was discovered by Qarin Van Brink. (By computer-implemented exhaustive search, it has been verified that the largest such collection does indeed consist of 9 cards.)
The top collection, of 21 cards, was constructed by David Van Brink, and is a basic geometrical extension of the 9-card collection. It has not been formally verified yet to be setless.
Oh. Of course it has a set; the middle row, containing a 3x3x3 cube, has 12 cards in it.
A 20-Card Setless Collection
This one was also constructed around the 9-card solution for the 27-card deck.
27 March 1997