Trog is one of those things that is beautiful in its simplicity- it's Noughts and Crosses (Or as some like to call it, Tic-Tac-Toe) inverted: the object being to NOT get 3 in a row.

Most people have experimented with Noughts and Crosses variants, such as going for larger grids, multiple players or higher dimensions (3 is common, 4 is, um, entertaining). The problem is that however you change it, everyone knows fundamentally how it works- but with Trog it's a whole new challenge. If only because of this familiarity with Noughts and Crosses, trying to avoid winning is counter-intuitive and new players often make the mistake of forgetting where they are and filling two (or if they're particularly unfortunate, three) adjacent cells.

Of course, all the tweaks that apply to Noughts and Crosses apply to Trog. 3X3 grids are generally considered dull, so the standard Trog board is 9X9. Some have experimented with 3-Dimensional (3X3X3) boards , but those can be painful to watch. Generally the best approach to Trog is to chalk up a massive grid and grab as many players as possible- preferably hung-over party guests at 3AM or students in general.

Another noughts and crosses bonuses that transfers well to Trog is that it's cheap and easy to set up. You can pretty much play anywhere, although for bigger games a blackboard and chalk (or if you're somewhat more modern than us and can handle the fumes, whiteboard and markers) is particularly handy for sheer scale.

Like Suicide Chess, the real strategy in Trog isn't in learning new moves but twisting the old ones: the least desireable cells in a grid for giant noughts and crosses become the most useful in Trog. Player approaches are varied- some scare their opponents into thinking they already know what they're doing through systematic choices of cells (every nth entry in every mth row) or by pausing thoughtfully whilst choosing; others grab cells instantly at random or shadow other players by picking a cell adjacent to the last one filled; on smaller grids some try to channel the opponent into losing positions even though this requires placing a large number of entries of your own close together; whilst Edge-huggers go for the perimeter cells simply because less cells join onto those ones.

I was introduced to Trog late at night at a party (gasps of amazement from those who know me) which happened to feature one of the creators himself, Tomos Bell. On his website (Http://www.tombell.net/games.html, also home of some other even more convoluted offerings) he observes that :

"Trog should only be played by those with nerves of polycarbonite, and preferably only those whose nerves are actually interwoven strands of Buckminster Fullerene - "bucky-tubes". Enough of the meaningless chemistry references. Trog is Noughts and Crosses taken to a new level, and moreover, a level composed of pure evil and darkness. Trog will corrupt your children and torture your soul. Trog is the lingering feeling of a half-remembered nightmare. Trog is the end of all."

In other words, it fries your mind, and as such comes highly recommended to anyone looking for an engaging diversion on a long journey (or in an even longer lecture). It certainly stole (lunch)hours of my life. Better still, turn it into a game for PC/PDA/Calculator so people have even less excuse not to play it...