Dear Dr Maths, I would [ ... ]

Using shells as counters you can form different number patterns such as triangular and square numbers, see picture below.

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Bibliographic details
Main Author: Steve Humble
Format: Newspaper Article
Language: English
Place of publication: Newcastle-upon-Tyne (UK) MGN Ltd 28.07.2011
published in: Evening chronicle (Newcastle-upon-Tyne, England)
Data of publication: 20110728
Online Access: available in Bonn?
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