A complete set of 81 cards isomorphic with those of the game Set showing all possible combinations of the four features, by CMG Lee. The icons are different to avoid copyright infringement. Considering each 3×3 group as a plane aligned in 4-dimensional space, a set comprises 3 cards in a (4-dimensional) row, with wrap-around. An example 20-card maximal cap set from https://web.archive.org/web/20130605073741/http://math.rutgers.edu/~maclagan/papers/set.pdf is shaded yellow.
Own work
Cmglee