Here’s the premise. You have a square grid of blocks, all of which start yellow. By tapping on blocks to toggle them (and their nearest neighbours) to orange, your aim is to recreate the target pattern, shown in the bottom left of the screen. Sounds trivial doesn’t it? Starting with a set of uniformly coloured grids, 3×3 is simple, 4×4 will take you a minute or two to figure out and then you’re into the real meat of Brain Teaser, with a 5×5 to solve.After a while, Rubiks Cube-style, you’ll evolve certain strategies for inverting patterns of blocks, but, just like with the infamous Cube, BrainTeaser is never easy. Not even close. And once you’re into trying to match the semi-random patterns presented, I can guarantee your brain really will explode.There’s a slightly gimmicky timer that runs along the bottom of the screen – this isn’t really needed and complicates what is already a game that’s quite challenging enough – apparently turning off the timer will be an option for the very next BrainTeaser update. There’s also a conceptual problem with the bottom-of-screen buttons in that ‘Reset’ starts you back at the easiest 3×3 grid, while ‘New game’ restarts the current puzzle/level. The functions of the two buttons are thus reversed from what you’d expect and this is the main reason the game loses a star in its rating.Also mentioned for the next update, at the time of writing, was a slightly easier learning curve, with the 5×5 grids (and beyond) banished further into the game. This is good news because, as you’ll find out, in BrainTeaser you need all the help you can get.