I intended this to be a necklace, but it ended up so long that I made it into a belt. Could still be worn as a necklace, though.
How: Chainmaille and beads.
( cutting technical details )
There are eleven sections of yellow beads, and each section has eleven beads.
Yes, this has symbolism! Else it would not be titled as it is.
Idris is Idris "Sexy" TARDIS (as named in the DW episode "The Doctor's Wife"). The blue beads represent her; varying shapes as she is variable, blue with stars and chatoyancy as she is a space-time ship, and Very Blue.
Her Thief is, of course, the Doctor. The yellow beads represent all his regenerations so far, eleven sections of eleven beads. Also, eleven represents duality and thresholds; there is no Threshold like stepping into the TARDIS with the Doctor.
The spiral is the time vortex that they travel in.
I am quite pleased with it. 8-)