Ключевые слова: background, brain, classic, color, colorful, concept, conundrum, cube, dice, drill, eight, entertainment, exercise, five, game, illustrative, intellect, intelligence, isolated, jigsaw, leisure, logic, mathematics, mentality, mind, nous, one, play, problem, puzzle, random, riddle, rubik, sequence, solution, solving, square, stage, the four, toy, training, two, white, workout,