S4T is a somewhat (much) harder version of SET. A S4T consists of four cards satisfying all of these conditions:
For example, these four cards form a S4T:
These, however, do not. See the difference?
It isn't guaranteed that there actually is a S4T to be found on the board. In this case you can add another row with the '+4' button, and if you're stuck you can always try a 'Hint'.
You can change the initial number of cards in the dropdown menu. From experience I know that a board of 32 or even 36 cards is the most comfortable (i.e. least frustating) starting point, but it is possible to start with a board of only 20 cards. A modified version of Peter Norvig's probability simulation gave that 28 cards is the smallest board with a larger probability of finding a S4T than having a to add a row.
SET was dreamed up by Marsha Falco in 1974, and first published by Set Enterprises, Inc. in 1991. The rights to the original game of course go the aforementioned. If Set Enterprises is reading this, let me know if you'd like to print a (limited) edition of S4T. We've been playing it at my department for a while now, and we'd love an official set of cards
The styling of this page is modified from Jacob Belanger's Game of SET, the solver is home-cooked. Note that to be able to save and retrieve a board and the starting number of cards, some data needs to be stored in your browser. This is completely harmless, I assure you. Leon Poot, 2019