Jigsaw puzzles are an old but timeless form of brain-training game. Players need to carefully observe and think to solve puzzles, gradually accumulating results to complete the entire picture and gain a sense of accomplishment. They are attractive to both adults and children. These games can exercise thinking skills, logical reasoning, shape and color recognition, and cultivate concentration and problem-solving abilities.
A 16-grid puzzle is a common brain teaser game. It involves placing the numbers 1 to 15 on a 4x4 grid, leaving one empty space. The player's task is to move the numbers next to the empty space to the empty space, arranging all the numbers in a left-to-right, top-to-bottom sequence (hereinafter referred to as the sequence puzzle). Therefore, this game is also called "Moving Fifteen," "Fifteen-in-a-Row," "Fifteen-in-a-Row Puzzle," and "Number Wisdom Board."
Actually, this game doesn't necessarily have to be played on a 4x4 grid, but it seems difficult to arbitrarily change the size of commercially available physical number puzzles, and the 4x4 grid offers the most moderate level of difficulty, so it has become the most common choice.
