The rules of the game are quite simple: Players must separate a set of 16 words into four categories based on common characteristics. Each of these categories is labeled with a color, which also signifies their difficulty level. Yellow is the easiest category, followed by green, then blue, then purple.

So, you feel a real sense of real accomplishment." Erhan Aslan, who teaches applied linguistics at the University of Reading in England, added that the game is likely so popular because of its shareability.