Threes is a game of multiples. It’s a game of combining pairs of numbers to make even bigger numbers. It plays on idea of a sliding puzzle, except the board becomes more populated the longer you play. A new piece falls onto the board after every slide, until the board is completely populated. The end goal is to end up with a board full of large numbers, hopefully in the greater double digits, and maybe even a triple, for a high score.

You play on a 4 x 4 grid, shaped like mahjong pieces, where you slide pieces up, down, left, and right. The game doesn’t really start until you begin combining your blue ones and red twos to create threes. Threes combine to make sixes, which combine to make twelves, etc. Every time you combine two numbers, the result doubles. Only multiples of three count towards your end score, thus the name of the game.

While Threes is largely a game about numbers, there’s lots of little touches in the game, including an unintended achievement system, where creating bigger multiples of three unlocks new personalities. Each multiple of three has a different face, and they’ll smile at each other if they can combine. Threes maintains a history of your previous scores, and includes a toggle to reduce animation frame-rate to save battery life if you’re out and about.

If you love games like Letterpress and Dots, you’ll love Threes. It’s easy to grasp and hard to master. It’s classy.

Threes is $1.99 on the App Store.