Stack app: The mesmerizing, beautiful free app game we can't put down

I like to keep at least one totally mindless, just-for-fun app on my iPad for some winding-down entertainment at the end of the day. Of course, Candy Crush and 1010 have dominated recently, but I've just discovered the Stack app (iOS and Android). And now I'm hooked.

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Stack is both beautiful and so simple (although, I do turn the volume off -- ugh). As you play the game, squares glide across the screen. When they're perfectly aligned with the top of the stack, you tap the screen to set them at the top of the stack. When you miss that perfect alignment, a chunk of the square falls off the side (like in the second shot) and the target area gets smaller. And harder to hit perfectly the next time. It's nice practice for your reflexes, and some simple, mindless fun. Hey, no judgement here. You can download the Stack app (iOS and Android) for free. Nice.