Explaining, convincing and proving

  • The Frieze Tree
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    The Frieze Tree

    Patterns that repeat in a line are strangely interesting. How many types are there and how do you tell one type from another?

  • Impossible Sandwiches
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    Impossible Sandwiches

    In this 7-sandwich: 7 1 3 1 6 4 3 5 7 2 4 6 2 5 there are 7 numbers between the 7s, 6 between the 6s etc. The article shows which values of n can make n-sandwiches and which cannot.

  • Mouhefanggai
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    Mouhefanggai

    Imagine two identical cylindrical pipes meeting at right angles and think about the shape of the space which belongs to both pipes. Early Chinese mathematicians call this shape the mouhefanggai.

  • Symmetric Tangles
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    Symmetric Tangles

    The tangles created by the twists and turns of the Conway rope trick are surprisingly symmetrical. Here's why!

  • A Knight's Journey
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    A Knight's Journey

    This article looks at knight's moves on a chess board and introduces you to the idea of vectors and vector addition.

  • Picturing Pythagorean Triples
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    Picturing Pythagorean Triples

    This article discusses how every Pythagorean triple (a, b, c) can be illustrated by a square and an L shape within another square. You are invited to find some triples for yourself.

  • Magic Squares II
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    Magic Squares II

    An article which gives an account of some properties of magic squares.

  • To Prove or Not to Prove
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    To Prove or Not to Prove

    A serious but easily readable discussion of proof in mathematics with some amusing stories and some interesting examples.