not quite the correct geometry, but puppy collective migration seems to have analogies with epithelial spheroids ;)

www.youtube.com/watch?v=Zzg-...

Interestingly, invasion later initiates near the regions that were originally sharp, where forces become locally concentrated, suggesting a form of shape memory.

What makes you take the first step out of going in circles?
Sometimes, it’s the time spent going in circles itself!

We studied how a ~500-cell spheroid breaks through a stiff matrix to initiate invasion.
The spheroid starts slightly egg-shaped (elongated), but instead of invading right away, it first undergoes a prolonged orbiting phase, during which it becomes nearly spherical. 🧵