Dobble


Dobble is a game in which players have to find symbols in common between two cards. It was the UK’s best-selling game in 2018 and 2019.
The game is sold as Dobble in Europe and Spot It! in the US. The name is a play on the word 'double'.

Gameplay

The game uses a deck of 55 cards, each printed with eight different symbols. Any two cards always share one, and only one, matching symbol. The object of the game is to be the first to announce the drawing in common between two given cards.

Development

In 1976, inspired by Kirkman's schoolgirl problem, French mathematics enthusiast Jacques Cottereau devised a game consisting of a set of 31 cards each with six images of insects, with exactly one image shared between each pair of them. In 2008, journalist and game designer Denis Blanchot found a few of the cards from the "game of insects" and developed the idea to create Dobble.
Dobble was released in France in 2009, and in the UK and North America in 2011 under Blue Orange Games. In 2015, the French board game company Asmodee acquired the rights to Dobble and Spot It!.

Mathematics

The special way that symbols are arranged on Dobble cards can be understood using geometry. If we represent each card by a line, and each symbol by a point where two lines intersect, then the properties of Dobble are that:
This geometric structure is an example of a finite projective plane.
If there are 3 points in each line this creates a structure known as the Fano Plane. This represents a simpler version of Dobble with 3 symbols on each card, 7 cards and 7 symbols.
In general, a finite projective plane with n+1 points on each line has n2+n+1 points and lines.
To represent the real game of Dobble, each line must join 8 points. This results in a structure with 57 lines and 57 points.
A pack of Dobble cards has 57 symbols but only 55 cards, so 2 possible cards are missing.