34 | NewScientist | 25 December 2010/1 January 2011

Letters selection boxFrom the Letters editorEvery now and then we receive letters that don’t quite belong on the letters page but that we would love to publish anyway. As it’s Christmas we have decided to ignore our own rules and start with a few of them. Thanks to everybody who has written to us this year – and apologies that we couldn’t print everything.With best wishes for the season

Numbers gameGraham Clarke of Edinburgh, UK, wrote to tell us about a remarkable three-level coincidence that he noticed when working on one of our Enigma puzzles.

The number 113 is prime, as is its mirror, 311. The squares of each, 12769 and 96721, are also mirrors of each other. For the treble, this second pair are respectively the lowest and highest of all five-figure squares that do not have repeated digits.

Can you think of any similarly remarkable coincidences buried in numbers? If so, head to bit.ly/ibweNH and tell us about them. We will publish our selection of the submissions in early 2011.

A limerick for CERNThe Scientists at CERN fill

with pride,As the Protons are set to collide.They’ll crash and they’ll splatter,When they measure the Matter,Will the Higgs be revealed, or

still hide?Keith FitzPatrick, The Netherlands

Catechismic chaosDid nature in creation spurt with

math as part of One, Or are numbers a religion making

all obey to Sum?Whatever be the truth of it I never

feel less grave, Than when Nature to The

Numbers, refuses to behave.Anna Tambour, Australia

The end of the world When you planned your super

collider, we doubted it would work. Now we marvel at the way you hid its magnets underground, energised its vital tubes in secret, threaded complex circuit wires, connected all the parts. Then you flipped the switch, caught me in its gravity.

You reassured it would not be the end of the old universe, not one last big bang. I realise now if you’re wrong we will never kn Norman Staines, UK

Raised handsFrom Gwydion WilliamsYour Instant Expert on the evolution of language says the selection pressures that

encouraged our heavy reliance on speech rather than sign language remain elusive (4 December). I have never used sign language, but it must be tricky addressing someone who is not already looking at you. I suppose there is no equivalent of shouting or whispering.

It would be worth consulting someone who habitually uses both, to learn more about the merits of the two modes.Peterborough, Cambridgeshire, UK

The editor writes:n Good point. The counter-argument is that there are certain disadvantages to speaking out loud, such as alerting predators and prey to your presence. It is also precluded in noisy environments.

Gentle robot handsFrom Francis FramptonSince I used to farm chrysanthemums, growing around 80,000 cuttings a year, I was interested in your report

on bean-bag “hands” for robots (30 October, p 23). Each of my cuttings was handled five times, which cost money and increased the risk of spreading disease.

I followed every avenue searching for methods to mechanise these five processes, but because of handling problems all my efforts failed. Now retired at 84, one glance at the technique illustrated made me think that Eric Brown’s group has a potential solution.

Now, chrysanthemums are peripheral to the demands of agriculture and horticulture, but the same problems are faced in the harvesting, grading and packing of fruit, planting trees and perhaps even catching insects for food. Within 15 years low-paid seasonal workers will become a scarce resource. Who or what will carry out these tasks then? Can this technology solve some of these problems in time?Bognor Regis, West Sussex, UK

What culture?From Bruce DennessKate Douglas’s description of the evolution of human culture (20 November, p 38) reminded me of an analysis I reported in the book Greenhouse Effect, Sea Level and Drought. This used archaeological and historical data to show that the world population growth curve is punctuated by steps of cultural evolution, each represented by a technological revolution.

The world population in 1390 (guns and ships revolution) was 312 million, in 1790 (second agricultural revolution) it was 625 million, in 1870 (industrial revolution) it was 1250 million and in 1950 (medical revolution) it reached 2500 million. In 1990, during the information technology revolution, the population was recorded at 5000 million. The population doubled increasingly rapidly perhaps because twice the number of

Enigma Number 1627

OPINION LETTERS

WIN £15 will be awarded to the sender of the first correct answer opened on Wednesday 2 February 2011. The Editor’s decision is final. Please send entries to Enigma 1627, New Scientist, Lacon House, 84 Theobald’s Road, London WC1X 8NS, or to enigma@newscientist.com (please include your postal address). Answer to 1621 Times square: the product is 216 The winner Eddie Crouch of Ripon, North Yorkshire, UK

AdRIAN SomERfIELdThose with a classical education will know that the sphinx was a riddle-setting monster associated with the Greek city of Thebes. I took the sum

ETA + BETA + THETA = DELTA and replaced letters consistently

with digits. Even if I told you the value of B, you still could not find all the digits, but if in addition I told you that PSI and PHI were prime, you could.

Please send in THEBES.

A riddle for the sphinx