Two things seen together on my kitchen table both recently acquired give me as much pleasure and provoke as much thought as anything I've ever owned. They are united in many ways being roughly the same size and designed for holding in the hand. Indeed their tactile aspects are equally satisfying: each gives an instant feel of inviting rightness and in each the thumb finds itself in an instinctive position of control.

Both are exemplars of the aesthetic principle of high modernism that perfection of function equals beauty of form. What separates them however is the distance between their moments of manufacture, a space of half a million years.

The iPod represents the future as imagined in my past, from the forties when I read of Dick Tracy's wrist radio and the fifties when I voyaged in space with Dan Dare.

The flint multi purpose tool (axe/knife/saw) from Tchad, whitened by millenia of wind and sand takes me on an opposite flight of the imagination to when it was held and used by a hairier hand than mine.

A third object on my table catches my eye and picking it up I find that my thumb reaches the controlling button at exactly the same point as the thumbgroove of the axe. Although the phone, patinated by a few years of studio use, is not so elegant as the axe, their length is, uncannily, exactly the same.