Here’s a little movie I made: Get the latest Flash Player to see this player. [Javascript required to view Flash movie, please turn it on and refresh this page] document.getElementById(“player1”).style.display = “”; var s1 = new SWFObject(“http://kisonecat.com/wp-content/plugins/flv-embed/flvplayer.swf”,”player1”,”320”,”240”,”7”); s1.addParam(“wmode”,”transparent”); s1.addParam(“allowscriptaccess”,”always”); s1.addParam(“allowfullscreen”,”true”); s1.addVariable(“height”,”240”); s1.addVariable(“width”,”320”); s1.addVariable(“displayheight”,”240”); s1.addVariable(“file”,”/wp-content/uploads/2009/01/mobius.flv”); s1.addVariable(“image”,”/wp-content/uploads/2009/01/mobius-poster.png”); s1.addVariable(“link”,”/wp-content/uploads/2009/01/mobius.flv”); s1.addVariable(“showicons”,”false”); s1.write(“player1”); I’m grading for the first year topology course at Chicago, and one of their homework problems asked them to show that pairs […]

I took my road test this morning—and I passed! After all these years, I am a licensed driver. Now, where should I drive to?

Google Trends plots the search volume (or some other measure? search percentage?) for a given phrase over time. It’s ridiculously fun! As an example, let’s look at the number of times people search for the words hot and cold. I downloaded the CSV file offered by Google trends to make the following graph: The […]

The Romans (among others!) wrote in wax with a stylus; the wax was embedded in boards, which were bound together in pairs. If a Roman were to place clay between these boards, could they make a copy of their wax tablet in the clay? It strikes me as remarkable that coins were minted so long […]

I’ll briefly introduce the Lights Out puzzle: the game is played on an n-by-n grid of buttons which, when pressed, toggle between a lit and unlit state. The twist is that toggling a light also toggles the state of its neighbors (above, below, right, left—although, on the boundary, lights have fewer neighbors). All […]

I made a movie recently for my advisor. The movie is so pretty, that I thought I’d share it here: may I present to you randomly drawn dots, where two dots are the same color when they touch! Get the latest Flash Player to see this player. [Javascript required to view Flash movie, please turn it […]

I’m again applying Granger causality to time series data from Intrade. This time, however, I connect box A to box B with a green arrow if A becoming more likely causes B to become more likely, and with a red arrow if A becoming more likely causes B to become less likely. Shorter arrows suggest stronger […]

Granger causality is a technique for determining whether one time series can be used to forecast another; since the Intrade market provides time series data for political questions, we can look at whether political outcomes can be used to forecast other political outcomes. There’s a library for the statistical package R to do the Granger test, […]

I made some movies of some of my favorite complexes: let be the -dimensional cube, and let be the edges around the origin, and let be the square face containing the edges and . Define a subcomplex consisting of the squares and all the squares in […]

Drew Hevle raises a very interesting question: suppose you are stranded on a desert island; what books would be entirely useless in this situation? Here are a few books that I wouldn’t want to be stranded on an island with: Federal Income Tax: Code and Regulations Selected Sections A Million Random Digits with 100,000 Normal Deviates Government Phone Book […]