The wooden base comes from the Gamal Tree. The Balinese make their furniture from the Gamal tree itself. Then the stumps are pulled from the ground & are soaked, the bark cleaned off & the wood is completely dried. The Artisan decides what design he wants the piece of upside-down wood base to take and, if necessary, shapes the wood by removing any extraneous pointy edges etc.  

He then hand-blows a piece of recycled glass that has been melted down and blows the molten glass into a piece of shaped glass & rests the handblown molten glass into the specific area of the wooden base where he has decided to place the vase, etc. The glass is allowed to partly cool in place & then the Artist finishes off the glass piece.  

This glass vase or shape will only fit in one place and in one specific direction on the wooden base.  The bottom of the glass item fits onto the wood and the formed glass is finished and polished to a high, smooth finish.  Red arrows are taped to both the vase & the wood to show the exact placement of the vase.  

FYI: No other glass vase will ever fit each location.