# Space-Pi!

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

# Geometric sand sculptures put your bucket-and-trowel creations to shame

The cubist creations of sandcastle artist Calvin Seibert will blow you away.

# 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."

# 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.

# 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.

# 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…

# 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…