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### Meta

# Category Archives: people

## 17×17 4-coloring with no monochromatic rectangles

Quick, what’s special about the following picture? As just announced by Bill Gasarch, this is a grid which has been four-colored (that is, each point in the grid has been assigned one of four colors) in such a way that … Continue reading

Posted in open problems, pattern, people, pictures
Tagged 17x17, four-coloring, graph, grid, monochromatic, rectangles
5 Comments

## Herbert Wilf: 13 June 1931 – 7 January 2012

I was sad to learn that Herbert Wilf died yesterday. Long-time readers of this blog may remember him as one of the discoverers of the Calkin-Wilf tree, which I wrote about in a ten-part series of posts (1, 2, 3, … Continue reading

## Book review: Magical Mathematics

Occasionally someone from Princeton University Press sends me a list of upcoming titles and asks if there are any I’d like to review. I jumped when I saw this one: a book about magic tricks and math! By Persi Diaconis … Continue reading

## The wonderful world of Mike Reilly

The other day I received an email from Mike Reilly, who introduced himself as a professional game and puzzle inventor, and suggested that I might be interested in taking a look at a few of his web sites. I wasn’t … Continue reading

## Vi Hart's math doodles

Vi Hart’s math doodle videos have been making the rounds of the math blogosphere (I heard of them from Denise at Let’s Play Math!). There are four videos so far and they are well worth watching — inspirational, creative, full … Continue reading

## The mathematics of human knots

Have you ever played “human knot”? It seems to be a common icebreaker/team-building sort of exercise (just do a Google search for “human knot” and you’ll find quite a few pages discussing it). Everyone stands in a circle, then reaches … Continue reading

Posted in games, people, probability
Tagged games, human, icebreaker, knot, team, teambuilding
9 Comments