Shatter Plate - with a twist

I started out this project as a gift for a house warming party. I was hoping to and up with a smaller serving plate, but ended up with an art piece. It was going to be a simple shatter plate. You take a hammer to a piece of glass and arrange it on top of another piece of glass. You can see in the second picture that when it was laid out in the kiln to fire it did not have a hole in it. When it was fired a bubble came up in the middle. I'm still not sure exactly why that happened. Not enough glass in the area? Defect in the glass? Who knows. The bubble was so thin that it popped back and forth just like the dice roller in a game of trouble. I decided to go with it and popped out the bubble and then ground the center out. I did a second firing for a fire polish, and then finally slumped the piece. We were able to pick up a stand on the way to the house warming and I ended up getting the project done in the nick of time.