I made these for March 14, 2015, since Pi Day was such a big deal.
Step 1: I Started With Inkscape
I created the pi symbol in Inkscape by importing an image of the symbol (from Word) and then added the loop to the top.
I used this Instructable to transform the image into a clear vector outline.
This produced the .svg file.
Step 2: Import the SVG Into Tinkercad
I imported the SVG into Tinkercad, and made it thicker. The link to the file is here.
Step 3: Print on a 3D Printer
I resealed the file in the MakerBot software (that is the 30m file). Then I created the set (the other .thing file).
We have a Replicator 2, and it printed on the first try (I used the default settings, with no raft and no supports).
Step 4: File Can Also Be Cut on the Laser Cutter
I think the loop is a bit weak, but the wood is pretty.
Step 5: Jewelry
I added cotton cord and jump rings and earring hooks for the final set. They are light and easy to wear.