Letter: Maths in the bathroom

Sir: Excited by the prospect of possessing my very own piece of practical Penrose tiling ("Kleenex art that ended in tears", 12 April), I purchased the last two-pack of white quilted Kleenex toilet tissue in my local supermarket.

Readers may be interested to know that in this particular Penrose tiling, made up of fat and thin rhombuses (squashed squares), the ratio of the number of fat rhombuses to the number of thin ones is equal to the Golden Mean (1.618 to three decimal places, or more precisely a half plus half the square root of 5). Of course this is only true if the rules for making the tiling have been followed exactly!

Rather than requiring that Kleenex dispose of all this toilet tissue, perhaps Professor Penrose could insist that a brief explanation of the tiling is included on the wrapper. There could even be a competition to discover how many sheets of the tissue are required for the ratio of fat to thin rhombuses to reach the Golden Mean, to, say, three decimal places. Although this might lead to queues for the lavatory, what better way to demonstrate to the British public that no aspect of life is untouched by mathematics and science?

ANNE TREVILLION

Paddock Wood, Kent