## Frank Morgan's Math Chat |

October 18, 2001

**Old Challenge**. How could you tell if the universe doubled back on itself?

**Answer**. Robert McDowell suggests that you could see yourself in the far
distance. Of course since people are so small, it's better to look for
recurring patterns of galaxies and other huge objects. Indeed, the 2001
Microwave Anisotropy Probe (MAP) satellite is looking for such recurring
patterns. One complication is that different copies may appear from
different perspectives. Freelance mathematician and MacArthur Foundation
"Genius" award winner Jeff Weeks has a computer program for finding such
hidden patterns.

**New Challenge**. What is the ideal size and shape for a TV set?

**John Horton Conway's On Numbers and Games**, one of my all-time favorite
math books, has now been reprinted in a new edition by A. K. Peters. It is
both a completely fresh reformulation of the foundations of algebra and
analysis, and a landmark treatise on combinatorial game theory. Conway's
incomparable originality, richly whimsical but rigorous style, and
mathematical brilliance come through on every page. No summary can do this
book justice, so I'll just say that everyone who loves mathematics will
find it an inexhaustible treasure. The second edition has added a prologue
and an epilogue, as well as dozens of improvements, corrections, and new
bibliographical references. Joe Shipman, Math Chat staff.

Copyright 2001, Frank Morgan.

Send answers, comments, and new questions by email to
Frank.Morgan@williams.edu, to be eligible for* Flatland *and other book
awards. Winning answers will appear in the next Math Chat. Math Chat
appears on the first and third Thursdays of each month. Prof. Morgan's
homepage is at www.williams.edu/Mathematics/fmorgan.

THE MATH CHAT BOOK, including a $1000 Math Chat Book QUEST, questions and answers, and a list of past challenge winners, is now available from the MAA (800-331-1622).