This clay stamp churns out endless seamless Voronoi patterns as you roll it with your hand. I've printed it in various sizes, all of which are sturdy and workable.

To scale the model, change the Size [World] setting in Prusa Slicer. Leave the Lock set and change the first value; the others will scale proportionally. Adjust the diameter to fit your hand comfortably and to meed the needs of the clay you want to stamp. Sometimes you want a finer pattern. Don't make it smaller than 63.5mm: the struts become too thin.
 

I've printed it in PETG with 25% infill. I enabled PLA organic supports but used a support blocker to limit supports to the bottom half of the model. (My first try I didn't use the support blocker, so I had to spend an hour tweezing out support structures from inside the Roly Poly.) The top prints fine without supports. I think you really only need supports for the bottom of the model. Prints great on Prusa XL.

The smallest size – 2.5" diameter – also makes a fine bouncy cat toy.

Check out my other clay stamp models in this Clay/Pottery Stamps Collection.

Created in Rhino 3D with Grasshopper.