Guy mentioned putting fibre optics in his roof lining and now I cannot find that thread. I did say that I would try and locate a photo of what i did a few years back on a party bus.
I'll put it here (not hijacking this thread) so you can see another effect
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Ray at Wigan Pier
2014 A8L D4 4.0TFSI Gold (Sticker says "Beige") Can't leave you in a black smoke cloud anymore..
In progress, Nothing left to do.
Gone 2004 A8 D3 3.0 TDI. Ebony Pearl Black (with little bits of other colours and glitter)