Reflection in a tabletop

It's rather a fun tabletop, made from broken glass held together in a cement base. It's quite heavy, and was one of the bar-tops used in Sunset Magazine's "Savor the Central Coast" event a few year's ago. They sold off bits and pieces after the event, and we secured this lovely (again, heavy) piece and found a sturdy base of it. It's graced our back garden or balcony patios ever since. I had never thought about it being reflective until I was sitting by it and noticed bits of our house and trees in its surface.