SET (Challenge version)

A two days challenge to code the SET card game (and adding a few twists (7 to find))

How to play :

You have to find SETS of 3 cards respecting the following rules :

For each one of the four categories of features — color, number, shape, and shading — the three cards must display that feature as either a) all the same, or b) all different.

Put another way: For each feature the three cards must avoid having two cards showing one version of the feature and the remaining card showing a different version.

Each feature exists in 3 versions :

color : red, green or blue,

number : one, two or three,

shape : diamond, oval or wave,

shading : empty, striped or filled.

There are a total of 3*3*3*3 = 81 cards. All of them are different, there is no duplicate.