# A Globe Can Help You Understand How Space Can Be Curved

There are theories out there that space itself can be curved. This is a confusing idea for some people. A quick exercise with a globe can make it a little more understandable.

# Space-Pi!

Pi is for planets, and spacecraft, for orbital dynamics and craters. It's 3.14, and it's all about circles.

# After 400 years, mathematicians have found a new class of solid shapes

The work of the Greek polymath Plato has kept millions of people busy for millennia. A few among them have been mathematicians who have obsessed about Platonic solids, a class of geometric forms that are highly regular and are commonly found in nature.

# I can't stop watching this door open & close

Add this to the list of things we never knew existed but now desperately need: The Evolution Door, a "flip-panel" invention by Austrian designer Klemens Torggler.

# All I want for Christmas are these badass Euclidian sculptures

From London-based "paper engineer" (paper engineer!) Helen Friel comes this creative collection of colorful folding geometric designs. The name of the collection? "Here's looking at Euclid." GEOMETRY PUNS! We must have these.

# How To: Make geometric models out of straws and coffee stirrers

Over at Make Magazine, Iann Gonsher shares this remarkably simple (not to mention totally free, if you count your latte as admission) method for building cool geometric models. "The baristas don’t tend to mind," he writes, "especially if you tip generously."

# A beautiful global map, created with a spirograph

Above is one in a series of world maps created by artist Rachel Evans using nothing more than a spirograph, the mesmerizing geometric drawing tool of your childhood.

# What does a heart's sine function look like?

In high school, you probably learned that trigonometric functions – like sine, cosine and tangent –can be derived, geometrically, from a circle (hence why trig functions are also known as "circular" functions). But what happens if you use a square to derive these functions, instead? Or a triangle? Or a heart?

# Whimsical, animal-filled illustrations of mathematical concepts

Kasia Jackowska's Drawing Mathematics series takes an unusually adorable approach to illustrating mathematical concepts. The Pythagorean Theorem and Sierpinski triangles are conveyed through drawings of elephants, snakes, and deer.

# 15 Uncanny Examples of the Golden Ratio in Nature

The famous Fibonacci sequence has captivated mathematicians, artists, designers, and scientists for centuries. Also known as the Golden Ratio, its ubiquity and astounding functionality in nature suggests its importance as a fundamental characteristic of the Universe.

# DeLand's Paradox is an illusion that can "disappear" a whole person

Let's say you are cornered by your worst enemy. They will kill you, but being an oddball enemy, they'll give you one request first. (And the request can't be "Don't kill me." They're on to that one.) I have a solution for you. Ask them to show you how DeLand's Paradox works. That will keep them busy for years while you…

# The Ultimate List of Reasons We Know the Earth is Definitely Round

In case you had any lingering doubts, here is some masterful cosmological/geological/geometrical instruction on our planet and its spherical — but not perfectly spherical — tendencies, courtesy of the ever-capable Henry Reich (better known as the creator, animator and narrator of MinutePhysics). Some great, if not…

# Is this the oldest d20 on Earth?

Romans may have used 20-Sided die almost two millennia before D&D, but people in ancient Egypt were casting icosahedra even earlier. Pictured above is a twenty-faced die dating from somewhere between 304 and 30 B.C., a timespan also known as Egypt's Ptolemaic Period.

# This optical illusion lets diagonal lines warp your brain

This optical illusion is a fairly simple one, but it's still a very impressive effect. A triangle and some cunningly positioned diagonal lines are all that's needed for your brain to tilt a perfect level rectangle completely off-kilter.

# According to a 1918 science magazine, the Earth would transform into a …

In the May 1918 issue of the youth science and current events periodical My Magazine, an unnamed author played it particularly fast and loose with geophysics when he declared that the planet was slowly becoming a pyramid. "What sort of people will live on the tetrahedron?" screamed the author in the headline, somewhat…

# The Eccentric Crank Who Tried To Legislate The Value Of Pi

There's an old urban legend about a state legislature that passed a law redefining pi so that it equaled 3. This story is a myth - but the true story that inspired it is actually even more ridiculous and bizarre.

# And now, the mathematics of pasta shapes

Have you ever wanted to know the mathematical formula for fusilli, or wondered about the geometric calculation for quadrefiore? Well wonder no more, for London architects Marco Guarnieri and George L. Legendre have written Pasta by Design.

# Delightfully weird Banach-Tarski video will make you wish you were a…

An oversimplified explanation of the mind-numbingly paradoxical Banach-Tarski theorem states that a solid sphere can be cut into non-overlapping pieces (geometricians would say that such a ball has been "decomposed"), and reassembled in a new arrangement, such that the end result is two identical copies of the original…

# Use Math to Cheat People out of Holiday Treats!

It's the skeeball prize wall of adulthood – a jar filled with candy, coins, or some other tiny trinket. A person at the front of the room compels you to guess the amount in the jar for free, or for a small donation to charity.