Cactus puzzle

Description

Goal: The goal of this puzzle is to get the ring out (and then back).

For some people this will be trivial and solved in seconds, and for others it will take multiple minutes.

The puzzle is inspired by models such as “the twig puzzle” or “the oksa puzzle”.

Print recommendations

Since this is for esthetic purposes I used a fine layer height.
Coarser would be fine too.
 

I recommend using a smooth plate for printing the cactus part, so that the two halves fit best.
For the ring and pegs, any plate will do.

Assembly

The assembly is done via press-fit pegs.
I recommend printing the cactus pieces, then printing one peg, check the fit. If too loose or tight, can change the scale by a few percents or retry. Alternativelly if too loose, inserting a thin paper-piece usually does the trick too. On Bambulab printers, the pegs just fit right away with only slight “convincing” needed.

Due to the ridged design the seam is barelly visible.
I recommend printing on a non-textured plate for best fit.
Since during usage there is only compressing force and no pulling the halves, press-fit is plenty strong for holding it all.

Paracord

The paracord needs to be installed post-hoc as seen in the pictures. Needs to be short enough that the ring cannot escape by simply silding above the cactus arms. It needs to be long enough that the cord still allows for the cactus to be fully “extended”; but not so long that the two parts separate.
I recommend first trying by just making a knot to test the length, and then after confirming doing the cut+melt soldering of the paracord.
I used a paracord with ~4mm diameter.