Researchers discover algorithm to create shapes that roll down pre-determined paths

Researchers have developed a method to construct solid objects that roll down pre-determined paths, which they reckon could have applications in quantum mechanics and medicine. The team of researchers were led by Bartosz Grzybowski, distinguished professor at the Institute for Basic Science in Korea, and included first authors …

[Paul Kinsler]

Associated material

A most fun paper; I'm impressed. It's a shame there isn't (afaics) a public version.

But there is a notebook thing related to the paper at

https://zenodo.org/record/8116413

or perhaps better here

https://github.com/yaroslavsobolev/trajectoids/tree/v1.0

Or even this "colab" page...

https://colab.research.google.com/drive/1XZ7Lf6pZu6nzEuqt_dUCHormeSbCCMlP#scrollTo=EgzSY__vVWVr

[John Brown (no body)]

Re: Associated material

If you want to see it in action visit any fairground and have a go on the sideshows. Most of them manage to "gimmick" things so they roll or fly in anything but the direction you expect :-)

[Bebu]

《To get a ball of malleable clay to roll down a simple path, you can force it down a specific path once, squashing it as you go. Take it to the top again, restart it from the initial starting point on the ball's surface, and it will roll down the same path.》

Not having access to the paper I would guess that the definition of "simple path" is pretty critical here. I can imagine for some paths the deformed ball reaches a point where any deformation that could move it along the desired trajectory will be evenly balanced with an alternate trajectory.

Sensitivity to initial conditions (position, velocity, ball mass) would also be a consideration I imagine.

Really "outside of the box" thinking which is refreshing.

Somehow reminds me of the white blob, "Rover" that guarded the Village in the original 1960s series "The Prisioner."

[Arthur the cat]

Slightly unfortunate name

Trajectoids sounds like either a Space Invader clone or something with a 27 month NHS waiting list.