Spider shroud

I went on holiday for two weeks and returned to find this ghostly impression of a spider on our toilet roll (see photo below), but no spider or spider body anywhere around. How did the spider cause this pattern?

(Continued)

• I take issue with a previous correspondent’s description of studying loo rolls as being “several orders of interest below watching paint dry” (25 March). The highly respected computer scientist Donald Knuth devoted a paper to the topic of which roll is more likely to run out first in a dual-roll dispenser, and there have been many studies of the social stratification of toilet paper orientation, as evidenced by the scores of references in the Wikipedia entry on the topic. Need I continue?

Richard Miller, London, UK

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