This ended up being a family project, in fact, we all signed the back. It's attached to the stud with predrilled holes underneath 4 corks that are subtly marked. 

The corks are mostly whole cork (non-amalgamated) and come from California and Washington wineries. 

This is piece is important to us for many reasons, one being that most New Zealand wineries have gone eco and use screwcaps. 

The mosaic was created on a custom made MDF frame by Ed Bigus, the glass is all stained glass and glass beads.

It was fun putting this puzzle together as a family.