Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:4766887.

We had a plant trying to take over the window sill recently by sprouding creeping tendrils. To give it a place to grow, I designed these three rings (that can be printed all at once if you nest them correctly). Using three wooden sticks (standard fare for orchids around here), you can turn the rings into a tower for creepers!

The hole diameter is 6mm. I imagine this could be extended with more rings, but I also think that the construction would get unwieldy pretty soon.

Check out my other designs, and let me know what you think!