Making a terrarium sounds so fun. I'd like to try one. I was trying to figure out what kind of container to use, and for that matter how to do it. I came across a site talking really basic stuff about building one. This would be just what I need with my absense of knowledge. However, one of the examples the poster showed was a bunch of wine glasses, each filled to the top with soil and sand and with 1 little succulent planted in the middle. What makes that a terrarium instead of just a potted plant? Now I'm confused again.