In 1971, a Japanese designer named Naoki Yoshimoto was working on what sounds like the least commercial problem imaginable: how many ways can you split a cube into two equal halves?
Most of us would get to "diagonally" and go back to our day. Yoshimoto kept going, and somewhere in that process he discovered something genuinely strange - a cube built from eight interconnected smaller cubes that could fold through itself, over and over, endlessly.
Turn it inside out and after a few folds you're back at a cube, except the faces that were hidden are now on the outside. Keep going and it cycles forever.
He first showed it in 1972 at a solo exhibition called "From Cube to Space", then produced it commercially as the Yoshimoto Cube.
And here's the detail I love...
It didn't get famous through marketing.
In 1981, a reporter from the Asahi newspaper visited New York and gave one to a curator at the Museum of Modern Art as a souvenir.
The curator was taken with it, and in 1982 the Yoshimoto Cube No. 1 entered MoMA's permanent collection, where it still sits. You can buy a reissue from the MoMA store today.
Fun fact:
Yoshimoto showed his cube three years before Ernő Rubik debuted his.
The original goes further than folding, too. Yoshimoto's cube dissects into two stellated rhombic dodecahedra (yeah, I don't know what that means either :-/) - two star-shaped halves that each somehow contain half the cube's volume.
It's a dissection puzzle wearing a fidget's clothes, decades before "fidget" was a product category.