I don’t wear hats very often. Occasionally I wear a baseball hat. Twice a year I wear the hat that accompanies my academic regalia. If you need to buy a hat, the first thing you need to know …| David Richeson: Division by Zero
I was looking for information about mathematics programs at other liberal arts colleges, so I put together this collection of links. I thought others might find it helpful, so I’m posting it here. (I actually asked ChatGPT to assemble this list. It did an OK, but not great, job. About 70% of the links were... Read More| David Richeson: Division by Zero
I’ve been playing around with Magic Eye images lately. Yesterday, I had the idea of creating an animated gif that shows the identical magic eye image for each frame. At first, the image looks like TV static (remember TV static?), but by unfocusing your eyes, you can see an image amid the static. Here are... Read More| David Richeson: Division by Zero
I use LaTeX to type mathematical documents. However, I often want to type mathematics when LaTeX is unavailable—for instance, in an email to a student, in a social media post, etc. To do so, I typically go to one of the many websites that offer “copy-and-paste” mathematical symbols, Greek letters, or subscript/superscripts. It is do-able... Read More| David Richeson: Division by Zero
The Mandelbrot set is one of the most stunning geometric objects in all of mathematics. In this blog post, I will show how to generate the Mandelbrot set below using Excel. It is also an example of how you can use AI (I used ChatGPT) to help with a task like this. (Here is the... Read More| David Richeson: Division by Zero
A few days ago, I posted templates showing how to fold a piece of paper so that you can cut out a hat or spectre tile in one cut. I decided to finish the trifecta: here’s a template to fold and cut a turtle tile.| David Richeson: Division by Zero
In the late 1990s, Erik Demaine, Martin Demaine, and Anna Lubiw proved that any pattern made from straight line segments in the plane—connected or not—can be cut out of a piece of paper by first making some strategic folds and then making a single cut. This is the now-famous Fold-and-Cut Theorem. (See Erik Demaine’s website,... Read More| David Richeson: Division by Zero
Suppose you want to design a drawbridge as shown in the figure below. A cable runs from the end of the drawbridge to the top of a tower and then down to a heavy counterweight that rolls along a curved track. The counterweight makes it easier to raise and lower the bridge. A natural question... Read More| David Richeson: Division by Zero
It is well known that we can make a cardioid by drawing straight lines inside a circle. Simply choose one point on the circle’s boundary to be the base point. Then, connect points on the circle to the points twice as far away from the base point (measured along the circumference). If there are n... Read More| David Richeson: Division by Zero
I’ve been enjoying the New York Times Connections game. It is a word game with simple instructions: “Find groups of four items that have something in common.” That is, you want to…| David Richeson: Division by Zero
8 posts published by Dave Richeson during May 2009| David Richeson: Division by Zero
Over the weekend I attended a May Day party thrown by one of my colleagues. During the party they had a traditional maypole dance. An example of a maypole dance is shown at left. A maypole is a tal…| David Richeson: Division by Zero
I’ve been on a weird kick lately making images using Excel. [Here’s one post. I hope to post more soon.] If you add a background color to each cell in a spreadsheet and resize the cell …| David Richeson: Division by Zero
Recently one of my colleagues was reading Alan Turing’s groundbreaking 1936 article “On Computable Numbers with an Application to the Entscheidungsproblem.” This is the article in…| David Richeson: Division by Zero
