The Bridges of Konigsberg

In old Konigsberg there were seven bridges:
Image: Wikimedia Commons

Villagers used to wonder: Is it possible to leave your door, walk through the town, and return home having crossed each bridge exactly once?

Swiss mathematician Leonhard Euler had to invent graph theory to answer the question rigorously, but there’s a fairly intuitive informal proof. Can you find it?

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A Tennessee Parthenon
Image: Wikimedia Commons

Nashville’s Centennial Park contains a full-scale replica of the Parthenon.

Like the original in Athens, it’s “more perfect than perfect”: To counter optical effects, the columns swell slightly as they rise, and the platform on which they stand curves slightly upward. So the temple looks even more symmetrical than it actually is.

Cadaeic Cadenza

Opening excerpt from “Cadaeic Cadenza,” a short story written in 1996 by Mike Keith:


A Poem: A Raven
Midnights so dreary, tired and weary,
Silently pondering volumes extolling all by-now obsolete lore.
During my rather long nap — the weirdest tap!
An ominous vibrating sound disturbing my chamber’s antedoor.
“This,” I whispered quietly, “I ignore.” …

If you write out the number of letters in each word, they form the first 3,834 digits of pi.

Nazca From Space

Most people are familiar with the drawings in Peru’s Nazca Desert:

It’s thought they were created by local peoples between 200 B.C. and 600 A.D. They’re remarkably well realized, considering that the builders probably couldn’t have viewed them from the air. Here’s a view from a satellite:

It’s easy to decide that they’re the work of visiting extraterrestrials — the airliners that first spotted them in the 1920s described them as “primitive landing strips” — but researcher Joe Nickell has shown that a small team of people can reproduce a drawing in 48 hours, without aerial supervision, using Nazcan technology. Still, well done.
(Top image: Wikimedia Commons)