My husband wears a lot of semi-flexible, silicone rings. He's got all different colors and widths. I thought it would be fun to make him more. These rings can be made without the flexy filament, I just thought this was a fun use.
This Instructable is a good starting off point for learning to make simple 3Doodled rings that you can build on and make fancier.
*Note: I am in no way affiliated with 3Doodler/WobbleWorks, just a fan of using their product in my classroom.
Step 1: BoM
3Doodler Flexy Filament
Step 2: Faux Finger
Roll up some paper, the width you want your rings and secure them with tape. I wrapped tape all around mine because it made it easier to remove the rings when I was done.
It doesn't hurt to use measuring tape to draw a steady circle around your faux finger.
Step 3: Doodle
Turn your Doodler on, insert filament. When the filament starts to flow, slowly turn the paper roll to wrap the filament around the ring. Don't worry about it not being straight. You just want to get a the foundation for a ring out. Flexy filament does seem to keep flowing even when the 3Doodler isn't actively running, I found it best to turn it off when I'm not using it immediately.
Step 4: Finish
Bend the paper a bit so that your ring pops off. Trim the edges if needed. The nice thing about flexible filament is that you can bend the ring without ruining it so you can even up your sides.