Ulam's Spiral: In 1963 mathematician Stanislaw Ulam found that if you count around a grid of squares in a spiral starting from the center and fill in all the squares that are prime numbers a pattern will emerge. This is called Ulam's Spiral, or sometimes a prime spiral. These 3 spirals were made in Matlab with the following code: (This version requires the image processing toolbox)

Mathematics

Surprising result: What is the volume remaining in a sphere with a 6" hole drilled through it?

function Spiral(n)

s=flipud(spiral(n));

t=isprime(s);

im2bw(t);

imshow(t);

axis('equal')

axis('off')

end

Are you impressed by savants who can recall the day of the week on any given date in history? Well don't be, anyone can do it. *Here's how*

A step-by-step method for the 4x4x4 Rubik's Cube.

This page is a kind of catch-all for things I find interesting. Some may be only indirectly related to mathematics....