So many adults are spending their days colouring in the lines, pencil companies are struggling to cope with the demand for coloured pencils and felt tip pens. Jenni Ryall is Mashable's VP of Content ...

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Believe it or not, Adult colouring books are topping Amazon Canada’s most-wished for and bestseller lists in Canada. The addictive, patterned books made up nine of the top 10 "most wished for" books ...