Gravity Block

If I were a betting man, I'd put my mortgage on Sir Isaac Newton being Steve Jobs's favourite scientist.

Exactly 320 years before Apple's first iPhone fell out of a Cupertino tree, the Oxbridge physicist-cum-mathematician-cum-astronomer was launching his own masterpiece, the Principia. In this seminal publication, Newton described gravity and the three laws of motion.

Developer Playsteria was clearly attracted to the First Law - you know, the one about objects at rest or moving needing an outside force to change its motion - since it forms the foundation of Gravity Block.

In this fiendishly clever physics-puzzler, the object is a wee orange inanimate cube, which must be negotiated through an 8-bit-styled landscape to an exit.

In its gravity-abiding path lie exploding blocks, reappearing block patterns, conveyor belts, black holes, coloured walls, switches, and - breathe out - wormholes.

Rather unusually, this heroic cube isn't under your direct control. Instead, the gravitational axis/pull is adjusted. In other words, you control gravity, not the cube. The screen is divided into four quadrants: up, down, left, and right. Tap on any sector and off the cube shoots in that direction.

30 levels are available and unlocked from the start - Easy, Medium, and Hard - while additional premium packs can be purchased via in-app payments. Minus the distraction of a timer, the only concern early on is matching or beating the par route to the goal. Think of it as golf, but without the walking or the sand.

In addition to its global leaderboard, which compares completed pack scorecards, OpenFeint records all manner of achievements, including the number of times the cube is destroyed.

Without a checkpoint system, prepare yourself for some serious lip biting and fist clenching in Einstein's Hard pack when your square ginger block meets its maker time and again.

An ethereal soundtrack is presumably included to soothe proceedings, but for the most part you'll be too busy figuring out a solution to notice.