Main link to MakePlayingCards.com at which sets of Steiner cards are for sale.

The author used to own a set of Steiner cards, made mid-1997. They had been laser printed onto white paper; laminated; and guillotined. That set, and many odd socks, have disappeared into the ether.

What is such a thing? Each card from such a Steiner(5, 6, 12) system has six letters from the first twelve of the alphabet, A … L, such that for any choice of five letters one card and only one card contains all five. Self-evidently, this is a thing of some mathematical elegance and symmetry. This mathematical toy is closely related to M₁₂, another beautifully symmetric abstract mathematical object.

The old deck was lost, so a new deck has been made. The 132 Steiner cards are divided into six suits of 22 cards (see StackExchange). MakePlayingCards.com has printed bridge-size cards = 2¼″×3½″ ≈ 57mm×89mm, and are available for purchase.

Each deck comprises 144 cards:

• 132 Steiner cards, being 22 of each of six suits. Each card has two different presentations of the letters: a 2×3 list of six characters; and a 4×3 box of twelve Booleans. For some games one presentation might be superior—player’s choice.

• Eleven jokers: one of each suit; one of each colour; and two generic (one ‘light’ and one ‘dark’). Of course, it might be that for some games all or some jokers are removed or deemed equivalent—game designer’s choice.

• One card giving credit and explanation, with “Please publish any interesting games devised for these cards, tagged ‘#SteinerKirkmanCards’.

Help wanted: by what non-intrusive non-spam means can group theorists be informed of this?