Letterlocking: the long-lost art of using paper-folding to foil snoops

"Letterlocking" is a term coined by MIT Libraries conservator Jana Dambrogio after she discovered a trove of letters while spelunking in the conservation lab of the Vatican Secret Archives; the letters had been ingeniously folded and sealed so that they couldn't be opened and re-closed without revealing that they had been read. Some even contained "booby traps" to catch the unwary. Read the rest

Acoustic meta-material: a shape that reflects sound but passes light and air

A Boston University team have developed an acoustic, 3D-printed metamaterial whose topology is such that it reflects 94% of human-audible sound; the researchers' demonstration involves inserting a ring of this stuff in a PVC pipe and blasting a speaker down one end: light and air emerges from the other end, but sound does not. Read the rest

Origami hand: "a disposable robot hand" made from folded paper

Tokyo grad student Tezuka Sota's "Origami Hand" is a robotic gripping hand whose plastic-coated, water-resistant folded paper is sterile, disposable, and free from moving parts and lubricants, meaning it can be used in difficult environments that are hostile to bearings and oils, like space or underwater. Read the rest

Twisty Vase, meet Useless Machine

What's better than a Useless Machine? One that is built on a clever, threaded "twisty vase" whose lid twirls open and shut! Read the rest

Shoelace knots fail catastrophically, thanks to 7 gees' worth of stress

Update: Whoops, David got there first!

In a new paper published in the Proceedings of the Royal Society, researchers from UC Berkeley reveal that shoelace knots do not gradualy come loose, as was previously supposed -- rather, they fail catastrophically and suddenly, thanks to strange and surprising stresses that they must endure. Read the rest

Fold-flat furniture looks like isomorphic illustrations when it's collapsed

Jongha Choi's Master's thesis for Design Academy Eindhoven involved the creation of "De-dimension" furniture, which collapses into a flat, easily stored form when it's not in use -- but when it's in its flat form, it looks like a perspective drawing of its expanded shape. Read the rest

Detangling enthusiasts trade snarled yarn to tease back into order

Online communities like Ravelry's "Knot a Problem" invite knitters to ship them their most tangled yarn, which they patiently unravel and wind into usable skeins, as a kind of knitting-adjacent hobby, one that combines problem solving with topology. Read the rest

Engraving a Klein bottle with an Eggbot

The Evil Mad Scientists were presented with a challenge: inscribe one of Cliff Stoll's hand-blown Klein bottles, an object of surpassing beauty and odd topology. They modified an Eggbot plotter to etch the surface of a Klein bottle with a diamond engraver attachment. Read the rest

Gravity-defying levitating superconductor on a magnetic Möbius strip

Andy from the Royal Institution made a large, suspended Möbius strip out of rare-earth magnets, then cooled down an object until it became a superconductor, and set it levitating and running around the track. The result is amazing, plus Andy's explanation is cogent and fascinating. Plus, gravity-defying levitation!

Levitating Superconductor on a Möbius strip

(Thanks, Ed!) Read the rest