Shameless self-promotion

If you happen to be in or near Carlisle, PA tomorrow (Friday, October 17, 2008, 6:00-7:30), come by the Whistlestop Bookshop. I’ll be signing copies of my new book Euler’s Gem. Light refreshments will be served.

Create your own word clouds

This post is not really math-related.  I discovered a cool website called Wordle, which you can use to generate custom word clouds. Here’s how Wordle describes itself. Wordle is a toy for generating “word clouds” from text that you provide. The clouds give greater prominence to words that appear more frequently in the source text….

Cutting and folding paper

Inspired by Chaim Goodman-Strauss’s recent video about symmetries, paper snowflakes, and paper dolls, I decided to post a few other paper-related videos. First is a video showing some cutting tricks for a Möbius strip. I show this to my topology class, then have them play around with Möbius strips—twisting them various numbers of times and…

Königsberg today

In 1736 Leonhard Euler solved the now-famous bridges of Königsberg problem.  It is often hailed as the birth of topology and graph theory. Although no graph appears in Euler’s paper, his argument is topological in spirit. (He proved another famous topological theorem a decade and a half later.) The problem is stated as follows. If a resident of Königsberg…

Topological claymation

For my first post, I thought I’d post a couple of short videos that I made earlier this year.  The inspiration was the following sequence of pictures I put in my book illustrating what I call the “double torus clothesline trick.” It seemed like everyone I showed it to had trouble following the sequence of…