WHO SAID: 'Of all things in life, there is nothing more foolish than inventing'? James Watt, that's who. With that in mind, we welcome all readers to the column devoted to foolish inventiveness.

Let us first catch up on some of the swivel chairs left spinning when we last met. J Clements uses his as a hemispheric location bathtime tool. He points out that if you place your chair carefully in the water when the plug is pulled, it will turn anti-clockwise in the northern hemisphere and clockwise in the southern, or it may be the other way round. Between baths, he uses it as a garden bindweed unwinder.

David Nicholls informs us of a magnet-enhanced swivel chair that enables seated Muslims always to face Mecca. Steph and Paul, taking a rest from swivelling at the office, recommend the use of the chairs to save models the trouble of spinning around on catwalks. If they are also abstract expressionist painters, they can swivel at will, 'sploshing the paint in transit'.

'A swivel chair placed in a gap in a fishing line,' advises Mark Walmsley, 'will prevent the line becoming tangled when it is twisted by water currents.' Alternatively, he offers a culinary tip: 'Place bowl of cream on swivel chair, hold whisk in centre of bowl, spin chair rapidly for perfect whipped cream suitable for insertion into small cakes.'

Rachel Hough offers several uses: for ignoring people; to create severe bruising and abrasions of the lower body when placed at desk; breakdancing for beginners; large-scale Subbuteo football; to make milkshake without blender; rotating restaurant for spiders; to reduce instance of whiplash among Wimbledon spectators. Geoffrey Langley suggests they may be 'rotated through 180 to avoid witnessing the ritual humiliation of British players'.

Alexandra Harley, while extolling the virtues of swivel chairs for beginners in leg-kicking Russian dance classes, says they also make terrific candelabras if hung properly from the ceiling. Chris Bovis suggests that the smooth running of swivel chairs may be enhanced by the application of caster oil.

'A swivel chair,' says Caroline Hull, 'enables one to indulge in gratuitous unmannerly tergiversation.' Mollie Caird says it is 'invaluable for a disabled dervish'.

Claire Paul lists the 20 love- making positions that utilise a swivel chair, 'but the base needs to be firmly anchored'. She does not, however, specify whether in 'Scotsman's Leap' it is the Scotsman or the leapee who should be in the chair. Suzanne Smith provides etymological support for the idea of swivel chair as sex aid, with the Old English swive (to make love to) clearly linguistically cognate with swifan (to swivel).

Reverting to our opening sentence, we invite readers' ideas for things which have not yet been invented but ought to be. Or at least might come in useful if they were. We are prepared to offer, to those whose ideas most impress us, at least five copies of Clive Anderson's new book, Patent Nonsense: A Catalogue of Inventions that Failed to Change the World.

Or we might give them instead to anyone supplying answers to the following questions: Where does the hole in a doughnut go when you've eaten it? (Ben Chisnall, 9) How do people with amnesia know they've got it? (Derek Newson, age unspecified).

As a pre-congratulation to all who care to think about these, our illustration from Patent Nonsense shows the 'Pat on the Back Apparatus', patented in the US in 1985 by Ralph R Piro to: 'Provide the necessary psychological lift to allow a person to overcome some of the 'valleys' of emotional life in a highly technicalised society that often postpones the level of immediate personal approval desirable for continued accomplishment.'

All ideas should be sent to: Creativity, The Independent, 40 City Road, London EC1Y 2DB.