The SPL champions have one point from two matches in Group E - three behind United and Villarreal.

BBC: Celtic's away-day blues

When I was a teenager I saw a website suggesting pi could be a song, with one as middle C, two as D, three as E, etc.

CNN: On Pi Day, finding strength in numbers

The digital rear-view mirror celebrated its dazzling premiere at the Le Mans 24 Hours in the R18 e-tron quattro and R18 ultra race cars which gave Audi a one-two-three win in the legendary race.

ENGADGET: Audi R8 e-tron to feature digital AMOLED rear-view mirror