A result of owning a cat and a compost bin. Cat does the capture, compost bin does the post processing....
It was a glass chopping board with black paper underneath for the reflection.
I use black perspex, which is highly reflective on both sides. The problem with glass mirrors or clear perspex/glass with black paper under, is that you get a ghosting effect due to the thickness of the glass/plastic. With the perspex I use you get the reflection off the actual top surface. You can get it here (500mmx500mm is the smallest size you can get away with. http://stores.ebay.co.uk/Sheet-Plastics-Suppliers/3mm-Gloss-Black-Acrylic-Sheet-/_i.html?_fsub=1758515017