NATURAL SELECTION

Vending machines are the closest modern man gets to his primitive hunter-gatherer ancestors. The food knows it's trapped but it's determined to use all of its food acumen to stop you from getting your hands on it.

The vending machine offers maybe 25 different sections filled with chocolate bars and crisps and maybe some gum. That's a difficult way to start - once you've settled on having trashy food, which do you choose? And then there's the added complication that, once you've chosen, say, cheesy Doritos, they have them in two different sections, north east and south west of the machine. Despite being the same, it's a dilemma which one you choose, and, since it's all behind glass, you have no tactile aid for your selection.

Is there any logic to the order items are placed in these things? Chocolate bar, gum, gum, chocolate bar, crisps, crisps, chocolate bar... You can't settle on chocolate and just look at the top two rows, because chocolate is all over the place. It's like that 3D chess thing they play on Star Trek.

Having made your decision you come to the complicated way in which you must get the item. Despite only have 25 slots to choose from, if you want something from the top left slot you have to punch in 3-4-E-7. There are bank vaults with easier combinations to crack that these machines. Are we actually programming a robot arm to grab our selection? Maybe we're programming a robot arm to construct another robot arm which grabs our selection.

Although the food knows it's trapped, it still won't come without a fight. That metal coil that runs down the length of the shelf is an easy target for Brother Twix - he's always quick with his little claws, clinging onto that thing for dear life.

There's certain secret information that vending machines won't share. Does this one give change? Is it exact change only? Does it take five pence pieces? Does it accept pound coins? Is it always a 50 pence piece that's needed? Is the dim light where it says "No change given" on now, or is that just a reflection?

Of course, the real fun of the vending machine is the price system. A 20p pack of gum can be anywhere between 35 pence and a pound. Chocolate bars start at 70 pence. What are these prices? Where do they come from? The machine's there, there's just the one guy servicing 200 a week - what's to pay for? Is there some secret board of vending machinists who pluck these prices out of thin air each month?

I guess it took a while for primitive man to discover fire. That freezing cold feeling that vending machine food has is an extra throwback to your hunter-gatherer roots - they throw that in for free.