16
https://plus.maths.org/content/issue/issue/16
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https://plus.maths.org/content/issue16
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<span class="date-display-single">September 2001</span> </div>
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<p>What colour is my hat? Why do we always seem to recognise faces? And what happens when you join up the midpoints of all of the sides of a triangle? Explore all this and more in this issue of Plus.</p>
16indexTue, 01 Jun 2010 12:30:28 +0000plusadmin5205 at https://plus.maths.org/contentRogue trading?
https://plus.maths.org/content/rogue-trading
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John Dickson </div>
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The dangers of trading derivatives have been well-known ever since they were catapulted into the public eye by the spectacular losses of Nick Leeson and Barings Bank. <b>John Dickson</b> explains what derivatives are, and how they can be both risky, and used to reduce risk. </div>
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<p>I think it is still safe to say that most people have heard of Nick Leeson. In early 1995, Nick Leeson earned global notoriety when it was discovered that he had lost around $1.3 billion trading derivatives, bringing about the collapse of Barings Bank, one of the world's largest at the time. Nick was sentenced to six and a half years in jail. On his release he became the darling of the chat
shows and his story has since been glamorised in a film.</p><p><a href="https://plus.maths.org/content/rogue-trading" target="_blank">read more</a></p>https://plus.maths.org/content/rogue-trading#comments16arbitragecall optionderivative instrumentforward contracthedgingoptionpremiumput optionstrike priceFri, 01 Dec 2000 00:00:00 +0000plusadmin2187 at https://plus.maths.org/contentAnswers
https://plus.maths.org/content/answers
<p><a href="https://plus.maths.org/content/answers" target="_blank">read more</a></p>16editorialFri, 01 Dec 2000 00:00:00 +0000plusadmin4961 at https://plus.maths.org/contentFrom quasicrystals to Kleenex
https://plus.maths.org/content/quasicrystals-kleenex
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Alison Boyle </div>
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This pattern with kite-shaped tiles can be extended to cover any area, but however big we make it, the pattern never repeats itself. <b>Alison Boyle</b> investigates aperiodic tilings, which have had unexpected applications in describing new crystal structures. </div>
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<p>The motto of the Nasrid kings who built the Alhambra of Granada was "God is the only victor". Allah is all-powerful: the Qur'an forbids the depiction of living beings in religious art lest it be seen as a blasphemous attempt to rival the creative powers of God. To avoid this, artists created intricate patterns to symbolise the wonders of creation. The repetitive nature of these complex
geometric designs suggests the infinite power of God.</p><p><a href="https://plus.maths.org/content/quasicrystals-kleenex" target="_blank">read more</a></p>https://plus.maths.org/content/quasicrystals-kleenex#comments16aperiodic tilingescherpenrose tilingperiodic tilingquasicrystalquasiperiodicitytessellationFri, 01 Dec 2000 00:00:00 +0000plusadmin2188 at https://plus.maths.org/contentPlus Magazine
https://plus.maths.org/content/plus-magazine-22
<p><a href="https://plus.maths.org/content/plus-magazine-22" target="_blank">read more</a></p>16editorialFri, 01 Dec 2000 00:00:00 +0000plusadmin5103 at https://plus.maths.org/contentOn the dissecting table
https://plus.maths.org/content/dissecting-table
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Bill Casselman </div>
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<b>Bill Casselman</b> writes about the intriguing amateur mathematician Henry Perigal, who took his elegant proof of Pythagoras' Theorem literally to his grave - by having it carved on his tombstone. </div>
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<h2>Henry Perigal 1801 - 1898</h2>
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<p><i>It is essential to true history that the minor and secondary phenomena of the progress of mind should be more carefully examined ...</i></p>
<p>Augustus De Morgan, in the Introduction to <cite>Arithmetical Books</cite></p><p><a href="https://plus.maths.org/content/dissecting-table" target="_blank">read more</a></p>https://plus.maths.org/content/dissecting-table#comments16congruencecut-and-shift proofdissection proofHenry Perigalhistory of mathematicslattice tilingPythagoras tilingpythagoras' theoremtessellationFri, 01 Dec 2000 00:00:00 +0000plusadmin2189 at https://plus.maths.org/contentFriends and strangers
https://plus.maths.org/content/friends-and-strangers
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Imre Leader </div>
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Sometimes a mathematical object can be so big that, however disorderly we make the object, areas of order are bound to emerge. <b>Imre Leader</b> looks at the colourful world of Ramsey Theory. </div>
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<p>In 1928, <a href="http://www-groups.dcs.st-andrews.ac.uk/~history/Mathematicians/Ramsey.html">Frank Ramsey</a> was wrestling with a problem in mathematical logic. To solve it, it seemed to him, he needed to show that the mathematical systems he was studying would always have a certain amount of order in them.<p><a href="https://plus.maths.org/content/friends-and-strangers" target="_blank">read more</a></p>https://plus.maths.org/content/friends-and-strangers#comments16chaoscolouringcreativitygraph theoryRamsey numberRamsey theoryFri, 01 Dec 2000 00:00:00 +0000plusadmin2190 at https://plus.maths.org/contentCareer interview: Aerodynamicist
https://plus.maths.org/content/career-interview-aerodynamicist
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Helen Joyce </div>
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<p><b>Christine Hogan</b> <i>graduated with a maths degree in 1991 from Trinity College, Dublin. She then embarked on a career as a computer programmer, system administrator and security consultant, working for start-ups, large companies, and as a self-employed consultant, in Europe and the US. In 1999 she started studying aerodynamics, with the intention of going into race-car design. Along the
way, she has studied law, taught computer programming, and written a book on managing computer networking security.</i></p><p><a href="https://plus.maths.org/content/career-interview-aerodynamicist" target="_blank">read more</a></p>https://plus.maths.org/content/career-interview-aerodynamicist#comments16aircraft wake vortexcareer interviewcomputer programmingdistributed computingobject-oriented programmingracecar designScience & EngineeringSportsystems administrationturbulenceFri, 01 Dec 2000 00:00:00 +0000plusadmin2401 at https://plus.maths.org/contentPuzzle page
https://plus.maths.org/content/puzzle-page-8
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Similar triangles and colouring the plane </div>
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<h2>Similar triangle puzzle</h2>
<p>Here is a puzzle which in some ways is similar to last issue's <a href="/issue15/xfile/">mystery mix</a>, though the solution is much simpler. In fact, you might want to have a look at that article first, to check that you understand the idea of "colouring the plane".</p><p><a href="https://plus.maths.org/content/puzzle-page-8" target="_blank">read more</a></p>https://plus.maths.org/content/puzzle-page-8#comments16puzzleFri, 01 Dec 2000 00:00:00 +0000plusadmin2846 at https://plus.maths.org/contentThe Interactive Geometry Software - 'Cinderella' Version 1.2
https://plus.maths.org/content/interactive-geometry-software-cinderella-version-12
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<h2>Cinderella</h2>
<p>by Jürgen Richter-Gebert and Ulrich H. Kortenkamp</p><p><a href="https://plus.maths.org/content/interactive-geometry-software-cinderella-version-12" target="_blank">read more</a></p>https://plus.maths.org/content/interactive-geometry-software-cinderella-version-12#comments16book reviewFri, 01 Dec 2000 00:00:00 +0000plusadmin3279 at https://plus.maths.org/content'Hidden Unity in Nature's Laws'
https://plus.maths.org/content/hidden-unity-natures-laws
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<h2>Hidden Unity in Nature's Laws</h2>
<h3>by John C. Taylor</h3>
<p>Avid readers of popular books on the laws of nature are tolerably familiar with a number of facts.<p><a href="https://plus.maths.org/content/hidden-unity-natures-laws" target="_blank">read more</a></p>https://plus.maths.org/content/hidden-unity-natures-laws#comments16book reviewFri, 01 Dec 2000 00:00:00 +0000plusadmin3280 at https://plus.maths.org/content'The Math of Money'
https://plus.maths.org/content/math-money
<div class="pub_date">Sep 2001</div>
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<h2>The Math of Money</h2>
<h3>by Morton D. Davis</h3>
<p>Money is peculiar stuff. It has no use of any kind apart from its value in exchange for something else, and this grows over time as it earns interest, or shrinks as inflation overtakes it.<p><a href="https://plus.maths.org/content/math-money" target="_blank">read more</a></p>https://plus.maths.org/content/math-money#comments16book reviewFri, 01 Dec 2000 00:00:00 +0000plusadmin3281 at https://plus.maths.org/content'Stamping Through Mathematics'
https://plus.maths.org/content/stamping-through-mathematics
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<h2>Stamping Through Mathematics: An Illustrated History of Mathematics Through Stamps</h2>
<h3>by Robin J. Wilson</h3>
<p>Robin J Wilson's book is "not", as he assures the reader in the Preface, "a history of mathematics book in the conventional sense of the word". No indeed.<p><a href="https://plus.maths.org/content/stamping-through-mathematics" target="_blank">read more</a></p>https://plus.maths.org/content/stamping-through-mathematics#comments16book reviewFri, 01 Dec 2000 00:00:00 +0000plusadmin3282 at https://plus.maths.org/contentMathematical mysteries: What colour is my hat?
https://plus.maths.org/content/mathematical-mysteries-what-colour-my-hat
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Mark Wainwright </div>
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<p>This is a game played between a team of 3 people (Ann, Bob and Chris, say), and a TV game show host. The team enters the room, and the host places a hat on each of their heads. Each hat is either red or blue at random (the host tosses a coin for each team-member to decide which colour of hat to give them). The players can see each others' hats, but no-one can see their own hat.</p>
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<p>This is a game played between a team of 3 people (Ann, Bob and Chris, say), and a TV game show host. The team enters the room, and the host places a hat on each of their heads. Each hat is either red or blue at random (the host tosses a coin for each team-member to decide which colour of hat to give them). The players can see each others' hats, but no-one can see their own hat.</p><p><a href="https://plus.maths.org/content/mathematical-mysteries-what-colour-my-hat" target="_blank">read more</a></p>https://plus.maths.org/content/mathematical-mysteries-what-colour-my-hat#comments16error-correcting codegame theoryHamming codeMathematical mysteriesstrategyFri, 01 Dec 2000 00:00:00 +0000plusadmin4752 at https://plus.maths.org/contentOpinion
https://plus.maths.org/content/opinion-3
<p><a href="https://plus.maths.org/content/opinion-3" target="_blank">read more</a></p>16editorialexaminationsmathematics anxietyFri, 01 Dec 2000 00:00:00 +0000plusadmin4866 at https://plus.maths.org/content