Infinity symbols, not bow-ties.So I don't think anyone else mentioned this, but on rewatching I noticed that Clara's black sweater is covered in bow-ties...
Infinity symbols don't generally have squared ends and a dot [knot?] in the center...
They sure look like bow-ties to me.



And didn't the Dalek version of Clara say she'd gone through an, ahem, 'phase' at one point? 