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

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

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)

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.

Mathematics