The Hoberman Switch Pitch Throwing Ball is a $12 toy that instantiates a dual polyhedron: every time you throw it, it turns inside-out; there's a wealth of scientific literature that explains how this works, including this open-access paper from the Journal of the International Association for Shell and Spatial Structures. Here's JWZ's summary: "The curved body panels that make it look like a sphere hide an internal structure that is a cube; or really, two tetrahedrons embedded in a cube; and when it its its activation energy, the tetrahedron becomes its dual, swapping faces and vertices." Read the rest
For Pi Day, Tasty posted this video of Ko telling her story while showing us step-by-step how she does her thing. It's so satisfying to watch, esp. that sped-up crust-weaving part.
Be sure to follow her pie-making adventures on Instagram. Since she started it in August 2017, she's gained over 150K followers, including Martha Stewart.
Here's a taste:
Friend or foetato? 🥔| Spud redux of my pear tart with red, purple, New, and sweet potatoes (all hand-sliced because I’m a masochist and I still can’t decide on a mandolin) and melty Raclette. Carbz and cheese: the lifespud of Mondays, amirite? 🧀
Dressed to the lines. 〰️| How else does one mow through @costco quantities of butter, flour, and sweet potatoes but with pie? Last week, I was scrounging the pantry. This week, I’m clearing house. #notsponsored, just anti-hoarding
What’s love quat to do with it? 🍊| Chocolate tart with chocolate glaze from @epicurious tiled with tangy kumquats. With Valentine’s approaching, consider this one luxuriant way to help you say “Kumquat may, I’ll love you to my pieing day.” (Even if it’s to yourself because let’s be real, you deserve every last crumbquat.)
The German geometer Max Brückner was fascinated by polyhedra, and he wrote about them in depth in his 1900 work Polygons and Polyhedra: Theory and History.
Over at the Internet Archive, they've scanned the book, and if you flip to the end -- beginning at page 243 -- there's a real visual treat: Several pages of Brückner's line drawings of polyhedra, followed by photos of his collection of 3D polyhedral objects.
The Public Domain Review recently unearthed these, and now I want some of these pages blown up to poster-size for my walls!
If you have two cubes of equal size, it's possible to cut a hole in one cube that's large enough for the other cube to pass through it.
In geometry, Prince Rupert's cube (named after Prince Rupert of the Rhine) is the largest cube that can pass through a hole cut through a unit cube, i.e. through a cube whose sides have length 1, without splitting the cube into two pieces. Its side length is approximately 6% larger than that of the unit cube through which it passes. The problem of finding the largest square that lies entirely within a unit cube is closely related, and has the same solution.
The original proposition posed by Prince Rupert of the Rhine was that a cube could be passed through a hole made in another cube of the same size without splitting the cube into two pieces.
High school teacher Joe Howard made another excellent math video. This time, he shows how Eratosthenes calculated the circumference of the Earth in 200 BC.
Read the rest
In one of the dopest displays of critical thinking in history, Erotosthenes estimated the circumference of the Earth. All he had was a pole, the sun, knowledge of a famous well in Egypt, and potentially money to pay someone to walk the distance between two cities. This story demonstrates the beauty of trigonometry.
Visual Center is a website that takes an image and attempts to find its compositional center point. It works well with designy images that have an obvious geometry to them and well-defined shapes to find and center — think logotype surrounded by whitespace. I'm not having a lot of success with photographs, though. [via] Read the rest
It’s a book of step by step drawing instructions. All you need is a ruler, compass, pencil and pen. While the geometry behind theses patterns is enormously sophisticated, actually drawing out the shapes is surprisingly easy and relaxing. It’s also a fun and painless lesson in geometry, especially for those of us not inclined towards math..