it's half full

As I was drinking water from a Mason jar this morning I set it down and wondered:

Question: Is it a jar or a glass?

Pondered that for a second then realized:

Answer: It's whatever I need it for. Maybe it's a vase, a pencil holder, a paint brush cleaner, a (not very stable) hat, a lightening bug catcher....

It's all in how you look at it.