Fancy yourself as a bit of a 'logical' person? Well, this puzzle game would give even a computer logic problems! Put simply, Logical is a game involving marbles and gears. Sounds simple enough? Well, it's not.

The object of the game is to get four marbles of the same colour into each gear on the screen. Initially you being the game with only a few gears to fill and no other complications. Marbles are released into tubes at timed intervals and your task is to guide them to the appropriate point.

The gears in the game resemble the dials from the non-computerised vertical boardgame Downfall. They're circular with four symmetrical holes at equidistant points. Unlike the Downfall dials, however, once the marble is in the gear, it stays there until you move it out - i.e. it won't fall out on its own.

The task then is to guide four marbles of a certain colour to a particular gear... which sounds fairly easy and indeed on the first level or so it's not too much of a challenge. Obviously, not all the marbles get released in the right order though - that would just be too easy. Instead they glide out seemingly at random and, if you're not careful, things can start to get confusing as marbles career into one another and start going off where you don't want them.

This is very much a game of 'putting things in and taking things out'. If, for instance, you've got a yellow marble in the tube leading to your gear and you need the red one that's behind it, the only way to get at the red one is to push the yellow one into the gear, turn it round one movement and pick up the red one then turn the gear back and send the yellow one on its way. Again, this all sounds very simple, but that's because you initially only have to worry about a few gears.

On later levels things are considerably less simple as you encounter numerous gears on a screen, often forming their own kind of maze. And that's not all. As you progress through the levels, new obstacles appear in the form of teleporters, colour stoppers and colour changers.

Teleports move the marbles to different locations on the screen, which can be a help but can also be a hindrance when the marble you need is beamed to totally the wrong place. Colour stoppers prevent marbles of a certain colour passing through them, and this can be a pain if the colour marble you want is blocked by another marble which can't pass through a colour stopper. And, of course, the colour changer turns one coloured marble into another one. Usually, this happens when you've got a marbe that you need and it inadvertently gets passed through a colour changer only to be become a marble you don't need.

Logical is a challenging, at times frustrating, game that is going to give puzzle fanatics hours of fun. The downside is that it's not quite as simple to play as a game like Tetris which means gamers less into puzzles might not find it easy to get into.